The four students—Kaylee Goncalves, Madison Mogen, Xana Kernodle and Ethan Chapin—were found dead in an off-campus house on November 13. Almost a month later, police have not named a suspect or made an arrest. The three women were roommates and Chapin, Kernodle’s boyfriend, was visiting.

In recent days, some of the victims’ parents have expressed frustration about how the investigation is progressing and the lack of information being provided to them.

In an interview with Fox News on Wednesday, Moscow Police Chief James Fry sought to reassure the families that investigators are working around the clock to apprehend the killer.

“I’m a dad with daughters, and it’s tough,” Fry told Fox News correspondent Alexis McAdams.

“We’re human. We don’t, we don’t go to these and just turn it off. It affects us but we have a job to do and we’re going to continue to do that job. We’re going to continue to push forward.”

Moscow Police have repeatedly said they believe the killings were a “targeted attack,” but have not given reasons. The department has also issued a list of people that they say are not believed to be involved.

On Monday, the department said it had not released additional details to the families and public due to the “active” investigation and it was “committed to providing information whenever possible but not at the expense of compromising the investigation and prosecution.”

However, Steven Goncalves, the father of Kaylee, has told the New York Post he has turned to private investigators out of concern that the detectives working the case are “inexperienced.” He has also called for police to release the alibis of some of the individuals that have been cleared. Kaylee’s mother, Kristi Goncalves, said she feels “there have been a couple of individuals that were cleared very fast that maybe should not have been.”

In a bid to reassure the families, Fry told McAdams that investigators “have all looked at the information that comes in and they’ve verified that those people can be cleared.

“So, what I want to assure them is we’re doing everything we can and we’re taking our time to do it right.” He also said this week that investigators were re-interviewing some people after new tips had been received.

In the Fox interview on Wednesday, Fry said he and other officers had “great pride” in the university and town and were committed to the investigation.

“We raised our families here. I’ve raised four children here,” he said.

“This is home and we have a great passion to serve this community. We love this community and we’re going to continue to serve this community throughout this situation until we reach an end.”