Police have arrested a 18-year-old suspect this week for killing two women, including a 80-year-old Roman Catholic nun, in Riga, local media reported on Friday.

Both murders were committed in Kipsala, a residential suburb on the left bank of the River Daugava, LETA news service reported, citing police spokesman Toms Sadovskis.

The suspect has already confessed to killing the nun and a 56-year-old woman, the head of the Riga criminal police Andrejs Sozinovs told journalists Friday.

The man intended to rob his victims. He is being probed for possible involvement in other crimes, according to the police.

The nun disappeared after leaving her convent to attend a church service on December 6. Her body was found under a pile of tree branches not far from her convent in Kipsala on December 14, with wounds showing she had suffered a severe blow to her head.

The body of the 56-year-old woman was found in a place not far from the body of the nun. Her head had a wound and her clothes was torn.