Police divers are at Lake Micmac in Dartmouth looking for clues in the slaying of Christina Kathleen Cline.
Cline, 27, was found dead in Shubie Park on Nov. 19.
Investigators spent several days searching the park and shoreline shortly after.
Police aren't saying what prompted them to go back.
"I can't go into the specifics, but I can say that based on the investigation to date, investigators have returned," said Const. Brian Palmeter, spokesman for Halifax Regional Police.
Cline was a single mother of three children. She lived in a duplex on Roleika Drive in Dartmouth.
A man out for a walk discovered Cline's body in an area of Shubie Park known as Vivian's Way.
Police said her slaying was not a random act.
Earlier this week, a 36-year-old man and a 25-year-old woman were arrested and questioned, but they were released without being charged.