By Tony Hanson

PHILADELPHIA (CBS) — A young woman has testified during a preliminary hearing that her boyfriend was attacked unprovoked and beaten to death near 4th and Chestnut Streets in center city Philadelphia last January.

Kerri Holland testified today that she and victim Kevin Kless were walking arm-in-arm, and another female friend was walking just in front of them, when Kless was pulled away from her by two men who attacked from behind and started beating Kless on the head (see related stories).

“It was an ambush,” Philadelphia prosecutor Brendan O’Malley told KYW Newsradio after today’s hearing.  “Initially a two-on-one becomes a three-on-one. The third person involved, the third defendant, throws the fatal blow.”

O’Malley says Kless was dead before he hit the ground.  According to an assistant medical examiner, that fatal punch snapped Kless’ head around, tearing an artery.

The defense says it has evidence — not presented today — that there was an exchange of words followed by a fight, and the charges in this case should rise no higher than manslaughter.

Kless had a blood alcohol level of .262 percent at the time of the altercation.  (The legal limit for driving in Pennsylvania is .08 percent; Kless’ was more than three times that, although he was not driving.)

The judge will consider written motions by the defense and prosection before deciding next month on the charges for trial.