A Maryland man has pleaded guilty to involuntary manslaughter for pushing a stranger who couldn't swim into Baltimore's Inner Harbor.

Twenty-one-year-old Wayne Black of Pasadena had been charged with first-degree murder in the death three years ago of 22-year-old Ankush Gupta of Boyds. According to Thursday's plea agreement, Black will be sentenced to four years in prison on Aug. 30.

Police say Black confessed to pushing Gupta, a University of Maryland engineering student, into the water in August 2008. They say he had visited the harbor to skateboard and asked Gupta for a cigarette, then shoved him in.