Appeal from the Circuit Court of Cook County 99 CR 17866 Honorable Sharon Sullivan, Judge Presiding
 The opinion of the court was delivered by: Justice McBRIDE
 A jury convicted defendant Dwayne Jackson of burglary. He was sentenced to four years' imprisonment. He appeals, claiming that (1) the evidence was insufficient to support his conviction; (2) the identification testimony of two witnesses should have been suppressed because it resulted from his illegal detention and an unnecessarily suggestive one-man showup; (3) the jury was erroneously instructed regarding identification evidence; and (4) the trial court erred in failing to investigate his posttrial claims of ineffective assistance of trial counsel.
 At trial, Daniel Burnham testified that in July 1999, he was a clerk at Ben's Liquor store, located at 15 East Ohio. The 15 East Ohio building also houses the Ohio East Hotel. The liquor store had two entrances: "[o]ne opening to the street, [and] one opening to the vestibule of the [Ohio East] hotel." There were 12 windows in the front of the store. Each one had a neon sign in it that "pretty much [took] up the whole window." In the vestibule area between the liquor store's two doors, there was no light fixture. However, there were some lighted signs surrounding the door. Those signs remained lighted when the store was closed. There were also "plenty of signs on both doors," none of which were illuminated.
 On July 8, Burnham's shift started at 7 a.m., but he did not arrive until 8 a.m. At that time, he noticed that the "window was broken in and there was paper scattered all over the place." Inside the store, "[t]here was a cigar box that had some phone cards in it that were --was on the floor, open and it was a bunch of papers scattered, and [Burnham] noticed some cigarettes missing and stuff, and that's it. It looked like [the store] had been broken into." Some phone cards and about 10 cartons of cigarettes were missing. Burnham started to clean up, but when he learned that Scott Robinson, a resident of the Ohio East Hotel whom Burnham had known for a couple of years, called the police, Burnham stopped cleaning. The police came, took fingerprints, looked around, and "started doing reports." Burnham spoke with the police. After they left, Burnham worked the rest of the day.
 Burnham also worked on July 23. That morning after speaking with Ebert Olson, a clerk from the Ohio East Hotel, Burnham called the police and told them that "the guy that broke into the store is out front." The police came. Burnham did not know Jackson and had not seen him around the neighborhood before the burglary. To Burnham's knowledge Jackson was not a frequent customer at the liquor store.
 Olson testified that in July 1999, he was employed as a desk clerk at the Ohio East Hotel, a single-residency dwelling, which was different from the Tokyo Hotel. *fn1 Olson's desk was located in the lobby of the hotel. A bar was off to the left side of the lobby, and the liquor store was off to the right. There was an entrance to the liquor store from the vestibule of the hotel. Olson explained that one of his duties was to keep people "from hanging around the vestibule, the lobby and the front of the hotel."
 Olson was working at 7:15 a.m. on July 8, when he noticed Jackson "hanging in the vestibule." Olson thought Jackson had "a white plastic bag" in his hands. Olson recognized Jackson from seeing him many times in the neighborhood, but he did not know Jackson. Olson went out and told Jackson "he couldn't hang out there." Jackson left. Olson went back behind his desk and sat there for 10 or 15 minutes. Then, he walked to the front entrance "just to look around." He saw Jackson sitting on a fire hydrant that protruded from the building. Olson did not see anyone else in the area at the time, and he returned to his desk.
 A few minutes later, Olson saw Robinson, who was a tenant in the hotel. Robinson went toward the side entrance to the liquor store. The store was closed. Robinson and Olson talked for a few minutes. Then, Robinson went back upstairs. When Robinson returned, he entered the lobby from outside and had a "[l]imited conversation" with Olson. Olson did not let Robinson use the phone at that time. About 20 or 30 minutes passed between the time Olson saw Jackson sitting on the fire hydrant and the time Robinson returned to the lobby. Olson never saw Jackson in the liquor store. Olson did not recall talking to any police officers on July 8. He did not remember any police officers in the liquor store or in the hotel lobby. Olson did, however, discuss with Robinson what Robinson had seen on July 8.
 On July 23, Olson started work at 7 a.m. At 7:30 a.m., he went outside and saw Jackson "in front of the hotel." Jackson was wearing "dark clothes," and he had a bucket. The clothes Jackson had been wearing on July 8 were "fairly darker" than the clothes he was wearing on July 23. Olson went and told Burnham, who was working in the liquor store, that "this was the guy that they claim was in the store." Olson did not give Burnham "a clothing description of the guy." He did, however, point the individual out and tell Burnham that he was walking west. Burnham called the police. After they arrived, the police brought Jackson into the lobby. Olson did not recall the police talking to him about what happened on July 8 before they brought Jackson into the hotel. Olson did not remember telling the police that the man who committed the burglary was walking down the street. Olson did not remember giving the police a description or having any conversations with the police. Olson did not remember telling the police that Jackson was the man he had seen in the vestibule two weeks earlier. Olson could not be certain that he had ever talked to the police about what he saw on July 8.
 Robinson testified that on July 8, 1999, he was living at the Ohio East Hotel. At 7:30 that morning, he went downstairs to get a pack of cigarettes from the liquor store. The liquor store was not open. Robinson went outside and started smoking a cigarette. Outside, he saw that a window at the base of the store was broken. He looked through the window and "saw some guy rummaging behind the counter." At that time, he could only see "a head or something moving around." He could not see the person clearly and thought it might be Burnham. Robinson "went up to the door on the inside." He knocked on the glass door. The man inside the store walked up to Robinson, "like face to face," and said "we're closed because we've been robbed." The man spoke to Robinson "[j]ust real quick," but Robinson said he could see the man's face, "no ifs, ands, or buts about it." Robinson had never seen the man before. Robinson went inside the hotel and told Olson to call the police. Olson told Robinson to call the police. Robinson called the police. Robinson went back outside, but "the guy had already fled." Robinson told Burnham that the store had been robbed, but he did not tell Olson what he saw. Then, Robinson went back upstairs.
 Robinson spoke with police officers on July 8 and gave them a description of the man he had seen inside the liquor store. Robinson thought he told the police that the man inside the liquor store "was a skinny, black dude." He also told the police that the man was wearing "something grayish *** like a gray T-shirt or something like that." He told them the man was around 140 pounds, around "30-ish, 35-ish." He told them the man was shorter than he was at 5 feet 11 inches. He might have said the man was "about average height, maybe a little shorter, like maybe five ten, five nine." Robinson could not remember whether he told the police the man had a medium or light complexion.
 At about 7:30 a.m., on July 23, 1999, Robinson came downstairs to get cigarettes. He "just got off the elevator [and said] there's the guy that robbed the liquor store." The "guy" was Jackson. Jackson was in the hotel lobby with another person. Robinson did not know who that other person was. After Robinson indicated that Jackson was the one who had robbed the store, he realized the other person was a police officer. Robinson gave a statement to a detective.
 Officer Michael Landando testified that on July 23, he was working in plainclothes with his partner, Officer Bill Walsh. At about 7:30 a.m., they received "a call of a man wanted for a robbery." They responded to 15 East Ohio, where they spoke with Olson "about the things that had caused him to make the call." Olson gave Landando a description of the individual he had seen and described the direction in which the individual was proceeding. Landando and Walsh "had observed an individual walking westbound from that location when [they] initially pulled up in front of the hotel." They saw Jackson, who matched the description given by Olson, walking westbound. Jackson had a white bucket with him, but he did not have anything from the liquor store. Landando thought Jackson was wearing a blue windbreaker. Landando and Walsh took Jackson into custody by putting his hands behind his back and handcuffing him. Then, they put him in their squad car and drove him back to the hotel to see if Olson could positively identify him. At that time, Robinson entered the lobby and said "that's the guy who robbed the liquor store." The officers escorted Jackson back to their squad car. Then, they took information from Olson and Robinson. They transported Jackson to the 18th District police station, where they advised him of his Miranda rights. Jackson told the officers that on July 8, "he was in the area there but he did not commit the burglary."
 Officer Drew Poynter testified for the defense that on July 8, he was working in uniform in a marked squad car with his partner Jim Dolan. Between 8:30 and 9 a.m., that morning, he went to Ben's Liquor Store at 15 East Ohio. Poynter noticed a broken window when he arrived at the liquor store. Poynter spoke with Robinson on the sidewalk in front of the store. Robinson described the offender as wearing gray slacks, dark clothing. He further described the offender as a light complected black male with a beard, 5 feet 11 inches tall, between 25 and 35 years old.
 Officer Walsh testified that on July 23, 1999, he was working in plainclothes with Landando. At about 7:30 a.m., they went to 15 East Ohio, where they spoke with Olson. They did not speak with anyone in the liquor store at that time. "Minutes later," the officers took Jackson into custody. The officers returned to 15 East Ohio with Jackson. Robinson was in the hotel lobby at that time. When Walsh claimed he could not remember whether there were other officers in the hotel lobby while he and Landando were there with Jackson, he was confronted with his testimony from a prior hearing, during which he stated that he, Landando, and "two other plainclothes officers that arrived on the scene" were with Jackson in the hotel lobby. Walsh did not speak with anyone in the lobby. A little later, Walsh and Landando took Jackson to the police station. At the station, Jackson informed Walsh that he was 5 feet 7 inches tall.
 Officer Gregory Horkavy testified that in July 1999, he was employed by the Chicago police department as an evidence technician. On July 8, 1999, he was assigned to work at Ben's Liquor store at 15 East Ohio. He arrived at the location at about 9 a.m. There were no other police officers at the scene at that time. Horkavy spoke with Burnham and Robinson inside the liquor store. Horkavy first noticed that about 98% of the second window from the right on the front of the window was broken out of the frame. Horkavy checked the glass and window frame for ridge impressions. Horkavy did not find any ridge impressions on the frame, but he did find some on glass fragments inside the store. The impressions were not complete. Horkavy also checked for prints at the counter and the cigarette area, but did not find prints in either location. Horkavy did not take any photographs at the scene. Horkavy did not take any elimination prints either.
 The parties stipulated that Officer Kovax of the Chicago police crime lab compared the prints lifted by Horkavy with Jackson's prints and "found that there were insufficient points to make an identification on the prints that were lifted by Officer Horkavy at the scene of the crime." The jury found Jackson guilty of burglary.
 On June 22, 2001, during posttrial proceedings, the trial court informed the parties that on May 22, a female juror "expressed that she had some concern with the verdict." She indicated, however, "that she did deliberate with her fellow jurors." The trial court also presented the attorneys with a copy of a letter written by another juror. In the letter, the juror indicated that he was "not quite sure justice was really accomplished" in Jackson's case. The trial court sentenced Jackson to four years' imprisonment.
 We first consider Jackson's claim that the trial court improperly admitted the July 23 identifications by Olson and Robinson. Jackson filed a pretrial motion to quash his arrest and suppress the identifications. Another judge presided over that hearing. At the hearing, Landando testified that on July 23, 1999, he was assigned to the tactical unit with Walsh. He was working in plainclothes, driving an unmarked vehicle. At 7:30 a.m., Landando saw Jackson half a block west of 15 East Ohio. Landando did not have a warrant to search or arrest Jackson at that time. Jackson was not breaking any laws. Landando "detained" Jackson and took him to the Tokyo Hotel at 15 East Ohio. At the hotel, Jackson was identified by Olson and Robinson. Jackson was then transported to the 18th District police station. At the station, Jackson was questioned about a burglary that occurred on July 8. Jackson supplied the police with his whereabouts on that day.
 On cross-examination, Landando explained that he was called to the Tokyo Hotel on July 23 because "there was a man wanted for a robbery at that location." As they approached the hotel, Landando saw Jackson walking westbound on the street, but he "didn't know at that point that [Jackson] was the guy." When he arrived at the hotel, Landando spoke with Olson, the hotel clerk. "[Olson] said that the guy who committed a burglary a couple weeks ago in the liquor store, which is adjacent to the Tokyo Hotel there, was just in the lobby and he just walked out the door and he was walking westbound on Ohio." Olson described the man and his clothing. Landando exited the hotel and "arrested" Jackson. When he brought Jackson into the hotel, Robinson said "on the day of the burglary, *** he observed [Jackson] inside the liquor store." That day, Robinson asked Jackson "what was going on," and Jackson responded, "we're closed. We just got robbed." Robinson told Landando that he did not know Jackson's name, but that he had seen him previously "in and around the Tokyo Hotel." He had also seen Jackson in the liquor store on other occasions.
 Landando stated that both Olson and Robinson identified Jackson as the person who had burglarized the liquor store. However, he conceded that Olson had not seen Jackson inside the liquor store on the day of the burglary. Olson did not see Jackson take anything from the liquor store or break a window of the liquor store. Instead, Olson had seen Jackson loitering in the hotel and told him not to loiter in the hotel. Jackson told Olson that he was waiting for the ...