Vigilant Philadelphia police yesterday recognized and arrested a third suspect believed to have stolen from a dying man as he waited for medical attention in an emergency room, authorities announced.

The man, Joaquin Rivera, a Latino community activist, musician and high school counselor, died of coronary heart disease last month in the ER of Aria Hospital's Frankford Campus, on Frankford Avenue near Harrison Street.

Rivera was 63.

Officers Princett Brooks and Robert Bakos on patrol yesterday morning recognized Jannia Walker, 21, of Erie Avenue near 13th Street, about four blocks from the hospital, the scene of her alleged misdeeds against Rivera.

Walker and two men allegedly took Rivera's wristwatch off his person, and it was caught on videotape that has been played on local and national media outlets.

Walker identified herself to Bakos and Brooks as "J.J." and was taken by the officers to Northeast Detectives, where she was subsequently charged with criminal conspiracy, robbery and related offenses, police said.

Richard Alten, 44, was arrested the same day Rivera died, and Martin Smith, 41, was nabbed Thursday.

Both men are homeless and have police records.

The case has prompted local and national outrage regarding health care for working-class communities. Rivera walked to the ER about 10:45 p.m. Nov. 28, complaining to staff of pain in his left arm. He was told to wait, and sat down in the waiting room. He never got up again. Rivera was pronounced dead shortly after midnight.

Councilwoman Maria Quinones-Sanchez, who has vowed to hold hearings about the case, has a meeting scheduled this afternoon with Aria Health officials to discuss the case.

The state Department of Health, Philadelphia police and Aria Health are investigating the case.