PORTLAND – A Portland teenager accused of stabbing a homeless man in the throat was charged with elevated aggravated assault, police said.

Matthew Digaetano, 19, was jailed on $20,000 bail. The victim, Michael Powers, 35, underwent a tracheotomy after the attack, according to Portland police Capt. Joseph Loughlin.

The attack occurred when two groups of men confronted each other on Portland Street near a homeless shelter and a community policing unit. Probation officer Scott Landry, who was in a nearby parking lot doing surveillance work, observed the fight and saw the suspect run away with a bloody knife, Loughlin said.

Some homeless advocates worried that Powers was attacked because he was homeless, but police said a motive and the relationship between the two men had not been determined.