Updated 12/30/10 1:34 a.m.

CHICAGO (STMW) – An 18-year-old suspect has been arrested and charged with the murder of Chicago Police officer David A. Blake, a member of the SWAT team who was shot to death last month.

LISTEN: Newsradio 780’s Lisa Fielding Reports

“It was a classic case of robbery; the suspect wanted to steal Officer Blake’s extensive gun collection,” said a police source.

Blake possessed a varied collection of registered and unregistered guns.

Bernard Williams of Chicago was charged at about 8 p.m. Wednesday with first-degree murder and armed robbery, said Sally Daly, spokeswoman for Cook County State’s Attorney Anita Alvarez.

Williams, who had lived with Blake for a short period of time, allegedly lured Blake, who was off-duty, to an out of the way location at a dead-end street in the 2900 block of West Seipp on Nov. 22 to “talk about moving in with him again,” the source said.

“It was a ruse to kill him and steal his cache of weapons,” the source said.

Blake, a 15-year police veteran who received 84 awards for distinguished service, was shot and killed inside his personal SUV after meeting with the suspect.

His gun and wallet were found at the scene, which originally led police to believe robbery was not a motive. A cigarette was still in the mouth of the 45-year old police officer when his body was found.

“The suspect allegedly returned to Blake’s house to retrieve Blake’s gun collection, but was unable to get inside Blake’s house because the police were already there,” the source added.

The suspect’s 25-year-old sister was a friend of Blake’s and the person who introduced the suspect to Blake. Phone records and an extensive probe of Blake’s personal relationships led to the suspect’s arrest, the Sun-Times was told.

The suspect reportedly told friends interviewed by police he had shot Blake and confessed to the crime late Wednesday.

He “provided them with a confession,” the source said.

The friends were brought before a Cook County grand jury on Wednesday, the source said.

“The case developed very quickly Wednesday after more than a month of extensive investigations by gang crimes units, homicide detectives and evidence technicians,” a source said.

Blake, who had served on the SWAT team for five years, was buried quietly and privately at the request of family members, the Sun-Times was told. “They did so to honor the memory of his mother, who had passed away,” the source added.

© Sun-Times Media Wire Chicago Sun-Times 2010. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed