A 63-year-old Israeli man told an immigration court today that he saw Karlis Detlavs, a Latvian emigre now living in Baltimore, beating Jews in Latvia on four separate occasions after the German Nazis overran the tiny country in 1941.

Boris Tsesvan, a dental technician who moved from Latvia to Israel in 1972, was the second Israeli witness in the deportation hearing who testified that he had seen Detlavs beating Jews during the Nazi occupation more than 32 years ago.

Detlavs, 66, who retired as a worker at the General Electric insulating plant in South Baltimore four years ago, is charged by the Immigration and Natuaralization Service with falsifying statements on his American entry visa in 1950.

The Immigrration Service, which wants to deport Detlavs for alleged war crimes, contends that Detlavs, from 1941 until 1977, was a member of the Latvian Legion, a Nazi-backed group, and that he participated in beatings of Jews.

Tsesvan, speaking through a Yiddish interpreter, said Detlavs "has changed considerably" since he saw him beating three Jews in 1941 and one Jew in 1943, but "this is the same man."

Detlavs' defense attorney, Ivars Berzins, of Babylon, N.Y., questioned yesterday's prosecution witness, Abraham Libchin. This morning, probing for details of Detlavs' appearance at the time Libchin said he witnessed Detlavs beating a Jew 36 years ago. Detlavs beating and shooting at Jews 36 years ago.

Libchin said he could not say exactly how much Detlavs weighed, how tall he was or what he wore.

"What you think, I examined him?" Libchin retorted. "I saw what he did. You think I thought I would remain alive another 40 years and come to America and testify against him?"