A woman was found dead from gunshot wounds in the house of her mother and her partner in Kiryat Ata in the North, police said early Wednesday morning.
The woman's boyfriend holds a licensed weapon.
Police suspect the woman may have killed herself but do not rule out foul play.
The victim recently joined the security company where her boyfriend worked. He was detained for interrogation on Wednesday morning.
Apart from suicide and murder, police also considered the possibility that the woman may have been killed by a stray bullet when her boyfriend was handling his gun.