Police are still looking for a Graduate School of Education professor who has been missing for nearly a month.

Professor of Education and Social Psychology Lawrence Kohlberg, who has worked at Harvard for 19 years, was last seen on January 17.

A spokesman for the Winthrop, Mass. Police Department said that they suspect suicide.

Police found Kohlberg's grey Volkswagon parked on a street next to Boston Harbor in Winthrop on the evening of January 21. There was no suicide note, but investigators found his wallet and topcoat in the car.

Chief of the Harvard Police Department Paul E. Johnson said yesterday that State and Boston police have been diving in Boston Harbor this week, but have found no evidence so far. He said he expects that the divers will continue searching.

Johnson, who is monitoring the various police efforts, said there have been no new leads since the police found Kohlberg's car.

Kohlberg's family and colleagues have suggested that his disappearance may be linked to a severe illness that has plagued him for the past 15 years.

They said that Kohlberg was depressed over the lack of improvement in the disease, which he believed was a parasite acquired while visiting Central America.