The victims attacker fled after the incident together with another man who acted as a look out, police investigators said.
However, members of the Scene of the Crime Office (SOCO) found strands of medium length hair that could possibly belong to the rapist.
The incident happened at 11:45 a.m. in the clinic along the East Service Road in Alabang.
Police declined to elaborate on the circumstances of the alleged rape except that the victim, who is in her thirties, reported the incident only at around 11 p.m.
Investigators led by Senior Police Officer (SPO) 4 Estela Formales are conducting follow up investigation into the incident to determine the identities of the two men. Nikko Dizon