A Philadelphia police officer testified in Municipal Court yesterday that he struggled to subdue a man whom he saw fatally stab another man on a busy North Philadelphia street corner on a Saturday afternoon.

At a preliminary hearing, Officer Jason Sommerville said he was off duty about 3 p.m. Feb. 14, driving south on Broad Street near Lehigh Avenue, when he saw Howard Cooper, 48, of South Philadelphia, chase Matthew Bullock, 32, of North Philadelphia, in the street and strike him in the face.

After hearing about an hour of testimony, Judge Jimmie Moore ordered Cooper held for arraignment June 23 on charges of murder and related offenses.

Under questioning by Assistant District Attorney Joanne Pescatore, Sommerville said he saw Cooper crouch over Bullock, who was on the ground, and stab him in the chest twice with a silver knife that was about seven inches long. He said he then saw Cooper stab the victim "at least 10 times."

"The male on the ground was rolling around" as Cooper stabbed him, Sommerville said.

Pescatore said Bullock was pronounced dead a short time later at Temple University Hospital of multiple stab wounds.

Sommerville said he approached Cooper with his gun drawn, told him he was a police officer, and ordered him to drop the knife.

He said he chased Cooper south on Broad Street for about two blocks to Cumberland Street, where he grabbed him and shoved him to the ground.

Cooper stood up with the knife in his hand and tossed the knife to the ground, Sommerville said.

"He grabbed me by my jacket and tried to slam me to the ground," Sommerville said. "I punched him numerous times in the face and chest."

Sommerville said that while he still had his gun drawn, four men walked toward him, and that one handed him a cell phone, indicating he had dialed 911.

The officer said he told a police dispatcher that he had Cooper in custody.

Cooper, however, said, "I'm not in custody yet," and jumped up and continued to struggle with him, Sommerville said.

Sommerville testified that Cooper then said, "I tried to kill that [expletive] and I'm going to kill you, too."

Cooper "kept repeating the same thing," Sommerville said. Cooper also said that "he was happy about all the officers that had been killed and that he was going to kill me," Sommerville said.

The officer said he subdued Cooper by punching him in the face and chest several times.

Under cross-examination by public defender Fred Goodman, Sommerville testified that the chase and struggle lasted between five and 10 minutes and that he did not strike Cooper with his gun.

Contact staff writer Vernon Clark at 215-854-5717 or vclark@phillynews.com.