PORTLAND – A volunteer emergency medical technician raped a woman a day after he helped her sick child, using a ruse that he had left behind a medical instrument to get into the family’s home, police said.

Scott Mondor, 31, of Harrison was held Friday at Cumberland County Jail on $10,000 bail on a charge of gross sexual assault.

Mondor was serving with the Casco volunteer rescue squad when he went on consecutive days to the woman’s home to help her sick toddler. He participated in both ambulance runs in which the child was taken to the hospital.

The mother and child were back at home Wednesday when Mondor returned and was allowed into the home to get medical instruments he said he left behind, said Cumberland County Sheriff Mark Dion.

Once inside the home, Mondor compelled the woman to have sex by threatening to harm the child, Dion said.

Dion said the case was especially disturbing because the suspect violated the public trust by using his position to commit a crime.

“You had an overtired, distraught mother who has been victimized by the person who came to her aid,” the sheriff said.

The woman reported the incident to deputies, who questioned Mondor late Wednesday and arrested him shortly after midnight.

Police are not aware of any criminal background for the suspect, Dion said.

Mondor, who is a car salesman in Windham, is a state-certified basic emergency medical technician and has been a volunteer with the Casco rescue squad since September, said Casco’s Deputy Town Clerk Lucille Griffin.

Mondor was placed on administrative leave.

Rescue workers are screened and hired in the same way as other town employees. That includes a check for any criminal record and a review of driving records, as well as a six-month probationary employment period, Griffin said.