Accused Craigslist killer Thomas Coffee told a Philadelphia jury Thursday that he did not kill the South Jersey man who responded to his online ad to sell an all-terrain vehicle.

The shots that killed Daniel Cook shortly after 11 p.m. on June 21, 2013, were fired, Coffee testified, by an off-road biking buddy of his.

The friend, whom Coffee could identify only by the name "Stead," admitted to him that he killed Cook, Coffee said. Coffee, of Willow Grove, said he was only selling the Yamaha Banshee ATV for Stead.

About the only thing Coffee knew about Stead was that he lived on Pierce Avenue, near his mother's home in Willow Grove, he testified.

Nor could Coffee explain why a .40-caliber round that matched those from the gun that killed Cook turned up in the suspended ceiling of his basement bedroom in his mother's house.

And he couldn't say why a cellphone was found hidden in his bedroom that belonged to an Oxford Circle teenager who identified Coffee as the gunman who robbed him on June 17, 2013.

"Another bad coincidence for you," remarked Assistant District Attorney Guy D'Andrea as he cross-examined the defendant.

Coffee, a lanky, 6-foot-plus man wearing a charcoal suit and black-rimmed glasses, readily agreed.

He also agreed with D'Andrea's sarcastic suggestion that Philadelphia homicide detectives planted the evidence. And he accused a homicide detective of punching and slapping him up to five times during questioning.

Coffee spent 90 minutes on the witness stand late Thursday afternoon as his attorney, Evan T.L. Hughes, began the defense's case.

In addition to Coffee's denial of any involvement in the Cook slaying or three other armed robberies for which he is on trial, Hughes told the jury that Coffee's sister would provide an alibi for the time of the slaying. Hughes said Shanise Palmer would testify that Coffee was at home around the time Cook was killed in West Oak Lane.

Speaking softly and haltingly, Coffee admitted setting up the meeting in front of his former family home at 6704 Hollis St. with Cook that night to sell Stead's ATV for $1,000 and a PlayStation 3.

Coffee said the meeting was for 9 p.m. and he was there with Stead, who brought the ATV. After an hour, Coffee testified, he was tired of waiting for Cook and left.

Coffee said he was on the way home when Cook called his cellphone at 11 p.m. to say he was on the block.

D'Andrea, however, cited earlier testimony by the victim's fiancee that when Cook called Coffee, a lanky man seated on the steps of 6704 Hollis answered his cellphone. Afterward, the man and Cook disappeared around a corner. Moments later, she heard three shots and found Cook dead on the street.

Earlier Thursday, Hughes made an attempt to challenge the integrity of the investigation into Cook's slaying by calling disgraced former Philadelphia Homicide Detective Ron Dove as a witness.

Dove was the assigned, or lead, detective in the murder probe. Several months after Coffee's arrest, he was fired after allegations that he covered up evidence of a murder by girlfriend Erica Sanchez and helped her flee. Hughes said Dove's legal problems should be known by the jury.

But Judge Glenn B. Bronson ruled Thursday morning that the pending obstruction-of-justice charges against Dove had nothing to do with Coffee's trial. Bronson said such information would confuse and prejudice the jury against the prosecution.

"You want him up there so you can dirty him up . . . to show he somehow obstructed justice in this case, for which you have not one scintilla of evidence," Bronson told Hughes.

Dove did testify briefly as the first witness in the defense case. He rebuffed suggestions by Hughes that there were improprieties in the probe leading to Coffee's arrest.

Dove also denied allegations in testimony Wednesday by Coffee's girlfriend, Alexis Green, who described her interrogation by Dove and Detective James Pitts. Green, who is African American, said Dove, who is white, called her a liar and referred to her by using a racial slur.

Earlier Thursday, Pitts, who is black, rebutted Green's allegation about being called a racial slur. "No one called [Green] that in my presence," he told the jury.

Sanchez was arrested Oct. 16, 2013, after several weeks as a fugitive for the stabbing death that Sept. 8 of her boyfriend, Cesar Vera, 33.

Dove, 43, who police say was having an affair with Sanchez, quickly came under investigation and was fired in November 2013. And in January, he was charged with hindering apprehension, conspiracy, obstruction of justice, and related crimes for allegedly helping Sanchez flee to Rochester, N.Y.