MANILA- The Senate on Monday began its investigation into a number of political killings in the country.

The inquiry, led by Senate committee on Public Order and Dangerous Drugs chair Senator Panfilo Lacson, aims to look into the killings and attacks on government officials, particularly in the local level.

• Mayors and Vice Mayors killed under Duterte administration

It also aims to probe election-related killings, including the murder of Richard Santillan, security aide of former Biliran Rep. Glenn Chong.

Police claimed Santillan was killed along with a female companion in a shootout in Cainta, Rizal on Dec. 10, 2018 after having been suspected of being part of the “Highway Boys,” a group allegedly involved in robbery, illegal drugs and murder.

Chong said his aide was on his way to give gifts to children, and had connected the killing to his senatorial bid.

• Glenn Chong says killing of aide related to senatorial run