Blake was murdered in November. On Thursday, prosecutors revealed that the officer may have been killed over his extensive gun collection.
Bernard Williams, 18, who was arrested for the crime, is the brother of a woman who was dating Blake.
Prosecutors say Williams wanted to sell Blake's guns for money.
Williams appeared in bond court Thursday, two days after his arrest. Saying that the presumption of guilt was great and the evidence against him strong, a Cook County judge denied Williams the possibility of bail.
Following the hearing, which several of Williams' family members attended, pastor Columbus Bland spoke on their behalf.
"The only thing that I can say is that we will be praying for him," said Bland. "We are not here to defend him or convict him."
Blake was shot while sitting in a parked vehicle in a Southwest Side neighborhood November 22nd. Prosecutors said Williams led Blake to a location referred to as 'Dead Man's Alley' because of its remoteness.
Prosecutors allege that Williams led Blake to the alley in order to kill him.
"The defendant had directed him to that location for the purpose of robbing him, shooting him, taking his keys to his home and his safe so he could steal those guns," said prosecutor Jamie Santini.
At a press conference Thursday morning, Police Superintendent Jody Weis said the lack of any witnesses made it especially hard to find a suspect.
"They were coming up without a lot of leads, so then it turns into that painstaking review of every type of record you can find, and the detectives were just relentless," said Weis.
Weis says Area One detectives came upon Bernard Williams as part of their investigation. After he was arrested, Williams allegedly told police he killed Blake for monetary reasons.
Weis also said that the two men knew each other.
"There was indication that they were meeting to discuss perhaps hooking up for that evening and watching a football game, or maybe living together at some point in time," said Weis.
At Thursday's bond hearing, prosecutors said Bernard Williams decided to steal Blake's gun collection after being invited to watch a football game at Blake's home sometime in October.
"It was then that he saw a safe that was located in one of the bedrooms," said Santini. "The defendant then began to inquire about what was in the safe. It was then that he learned that there were guns in the safe."
Prosecutors said that Williams's sister helped to set up the meeting that ended in Blake's death, but as of Thursday evening, the sister had not been charged.
"The defendant had asked his sister to call the officer and tell him that he had left some items back at his house that he needed to retrieve," said Santini. "The defendant's sister agreed to do this."
Williams will be back in court on January 18th. Blake was a member of the SWAT team and a 15-year police veteran.