NEWTON, Mass. (AP) — A couple celebrating their 50th wedding anniversary were stabbed to death, along with another family member, in what law enforcement officials said was probably a random attack.

The bodies were found in a home in Newton when the couple failed to arrive at church Sunday morning, police said. Police worry that the killer or killers may be still at large, and residents in nearby neighborhoods were urged to remain vigilant.

“Two of the individuals were celebrating a golden wedding anniversary this weekend. As you can imagine, this would be tragic on any day. To have family gathered for this kind of a celebration makes it particularly tragic,” Middlesex District Attorney Marian Ryan said Sunday evening.

Preliminary investigation indicates that there were signs of forced entry and that the victims were stabbed, Ryan said.

“Their 50th anniversary was to be celebrated in a blessing after communion at the 10 a.m. Mass," the Rev. Dan Riley, of Our Lady Help of Christians, told WCVB.com. "I can’t go into the details about who discovered them — but we became notified, and myself and a number of the staff spent the day there."

He described the three people killed as “three beloved parishioners — salt of the earth people, just great, great people."

There was an attempted break-in about a half-mile from the victims' home early Sunday, but it’s unclear if the two crimes were related, Ryan said.