Police discovered a mother and son dead in their Clifton, NJ home this weekend that they believe was a murder-suicide. Authorities say that 20-year-old Robert Regazzi shot his mother, 53-year-old Cheryl Regazzi, before he fatally overdosed on some type of narcotic. Police are unsure what prompted the shooting.

The bodies were found Saturday afternoon by a family friend. Cheryl Regazzi was killed by a single gunshot wound; several guns were removed from the home after the bodies were discovered. Chief Assistant Passaic County Prosecutor John Latoracca said it would take three or four weeks before authorities would receive the results of toxicology tests on the narcotic Robert took to overdose.

Authorities aren't sure when the shooting occurred, but NorthJersey.com reports the family put out their garbage cans Thanksgiving night for a Friday pickup—and they were still there as of Saturday morning. Neighbors told NBC that the two lived together and appeared close—Robert's father Jacques died in the mid-90's.

The mother and son were often seen taking walks together in the neighborhood with their dog. "It's a shame," said neighbor James Kirwin. "He really was a nice person. Why that happened that way, I don't know."