LOS ANGELES — Los Angeles County sheriff’s detectives are investigating the stabbing of a transit bus patron by another rider.

The department said late Monday the victim was in grave condition and was not expected to survive.

The assault occurred shortly after 10 a.m. Monday as the bus was traveling on Whittier Boulevard in East Los Angeles.

A man estimated to be in his mid-30s to early 40s used a knife to stab the other man multiple times in the upper torso. The assailant then got off the bus and ran away.

The victim, described as being in his mid-20s, was taken to a hospital.