A woman faces an assault charge in connection with an incident inside a hospital on the weekend, said police.

Officers said a hospital cleaning woman posed as a nurse.

Around 3:45 p.m. Saturday, officers were at Concordia Hospital with a 25-year-old man who had been arrested and was getting medical treatment before heading to jail.

Moments after the man was cleared by a doctor, it's believed a woman dressed in scrubs, similar to those worn by nurses, approached the 25-year-old and told him it was time for his sponge bath.

Sources said a syringe and a hospital tooth brush, with a sponge on the end of it, were brought into the room and set on the food table. The man was told to open his month and suck on the sponge for his breath. At first he refused, but then complied and his mouth was swabbed.

Officers became suspicious and approached a head nurse.

The suspect's hospital identification tag was on backwards. When flipped over, it revealed she was a cleaning staff member.

Officers took the woman into custody.

The Winnipeg Regional Health Authority said it will launch an internal review.

"The police are investigating and we are co-operating with police as well as conducting our own investigation," said Heidi Graham, a spokesperson for the WRHA. "At this point we have no reason to believe there are any other circumstances like this."

The suspect is charged with assault with a weapon, with the weapon being the unknown substance in the syringe.

The 25-year-old man approached by the female suspect is now in custody at the Winnipeg Remand Centre for his earlier arrest. At this point, the man has not become ill from the substance put into his mouth, said police.

Sources said toxicology tests are being conducted to see what the substance may have been.

The man apparently described the incident as creepy, but did not return a call from CTV News Monday for an interview.

Teresa Sawatzky, 41, has been charged with one count of assault with a weapon for the incident, said police.

CTV News contacted her on Monday.

"I didn't have a needle. They were saying I had a needle but I didn't," she said. Sawatzky declined to comment further on what she was doing at the time of the incident.

Sawatzky, who has no prior criminal record, has been placed on administrative leave.

- with a report from CTV's Stacey Ashley