A Muslim couple who emigrated from Bangladesh 30 years ago were found slain in their California home on Sunday, with a chilling note saying 'Sorry, my first kill was clumsy.'

57-year-old Shamima Rabbi, who worked as an accountant and her husband, 59-year-old Golam Rabbi, who worked as an engineer and also taught at a local junior college, were found shot in their house.

According to the NBC, the note continued by stating "I can't be like you, telling a lie. I can't love someone without telling them," although police have not confirmed it.

Police have released few details about the killings of the couple, including a possible motive. But police said in a statement Tuesday that investigators believe the killings were not a random act of violence and that the killer or killers were familiar to the family.

Investigators have talked to the couple's 16-year-old son, but have not been able to find the Rabbis' 22-year-old son, who was not named.

Detectives are attempting to locate him for questioning. He is not considered a suspect at this time.

Police spokesman Sgt. Enrique Garcia said the couple was shot in their home before relatives found them Sunday afternoon. It was not known how long they had been dead.

Friends and relatives remember the couple for their kindness.

They often had relatives stay with them as a first step in their own journey from their native Bangladesh to the United States.

"I have no words to explain how I am feeling," the couple's nephew, Golam Mustakim, said Tuesday. "I want to believe they are still alive."

Mustakim and his family emigrated from Bangladesh in 2000. Upon arriving in the United States, they stayed with the Rabbis in their four-bedroom home in San Jose.