BENGHAZI, Libya (Reuters) - A police officer was found shot dead on his Benghazi farm on Saturday, the latest in a series of attacks targeting police in the eastern Libyan city, a security official said.

The official said that Lt. Col. Nasser al-Maghrabi's body showed evidence of having been beaten before he was shot.

"Maghrabi's family found his body lying among the olive trees on his farm. He had two shots in his legs and one in his chest," said the official, who declined to be named.

Benghazi is the cradle of the uprising that ended the rule of longtime Libyan leader Muammar Gaddafi, and is now a hot spot for violence, riven with armed factions. Police and military personnel have been the frequent targets of attacks.

Earlier this week, the head of Benghazi's criminal investigations unit was abducted by an armed militia. He has been missing since.

In November, Faraj al-Deirsy, head of Benghazi police, was shot dead in front of his house.

Numerous police stations and checkpoints in the city, Libya's second biggest, have been targets of home-made bomb attacks.

"Maghrabi didn't have any personal problems with anyone and kept to himself," said the security official. "His death seems to be connected to the string of attacks on the police force in Benghazi."

The U.S. ambassador to Libya and three other Americans were killed in an attack on the U.S. consulate in Benghazi in September.

Police and legal experts have shied away from investigating the attack because they say they have not been guaranteed protection from the groups they believe were responsible.

Libya's new rulers have struggled to impose their authority on a myriad of armed groups, who helped oust Gaddafi in 2011 but have yet to lay down their arms.

(Reporting by Ghaith Shennib; Writing by Hadeel Al-Shalchi; Editing by Rosalind Russell)