A man in his 50s died Tuesday afternoon after collapsing on the east side of Monte Vista Avenue just south of Base Line Road.

Witnesses called the Claremont Police Department at 3:30 p.m. to report seeing a man that had been walking collapse on the sidewalk. Police have not released the man’s name, pending notification of next of kin. They estimated him to be about 57 years old.

Responding fire and police personnel performed life-saving measures on the man, but were unsuccessful.

“He succumbed to whatever  illness he had and/or issues,” said CPD Lieutenant Brian Thompson. “LA County Coroner is on scene. Doesn’t appear to be any foul play and it appears to be of natural causes at this time.”

The northbound number two lane of Monte Vista was closed for about four hours during the investigation.