BEIRUT, Lebanon — The Lebanese police have accused Syria of orchestrating the kidnapping of Syrian dissidents in Lebanon, a country that has served as a haven for them since the uprising against the government of President Bashar al-Assad began nearly eight months ago.

In one case, Shibli al-Aisamy, 89, a founder of Syria’s governing Baath Party who has become a leading voice of dissent against Mr. Assad, disappeared in late May while visiting his daughter outside Beirut. He went out for a walk and was picked up by people in a black sport utility vehicle, who spirited him across the border, the Lebanese police said.

In another case, the police said, three Syrian brothers, the Jassems, were kidnapped in February by rogue members of the Lebanese security forces using Syrian Embassy vehicles, again black S.U.V.’s. The Jassem brothers have not been heard from since.

In closed-door testimony before the Lebanese Parliament in October, the head of the Internal Security Forces, Gen. Ashraf Rifi, said Syria was behind both kidnappings and presented a detailed report with license plate numbers, cellphone records and statements from witnesses that he said implicated Lebanese security officers and tracked the cars to the Syrian border.