Thunder Bay police are saying little at this stage about a serious assault in the city's east end that happened just after 9 p.m. Thursday in a McLaughlin Street apartment building.

Police report one person was taken to hospital and is being treated in the intensive care unit, and one person is in custody.

The incident happened at McLaughlin Court, a 12-unit apartment building for single people and families, located in the street's 800 block. The building is operated by the Thunder Bay District Social Services Board.

On Friday afternoon, police were still holding the scene as they continued their investigation.

Investigators are asking anyone who witnessed the incident to contact the police's Criminal Investigations Branch.