Stonnington Crime Investigation Unit detectives are investigating the theft of a dog from a property in Malvern East last month.
Investigators have been told a male and female attended the Camira Street address about 9.30am.
They entered the backyard and took a male dog named Bruiser.
Two teenage occupants of the house attempted to get the dog back, but the male offender threatened to stab them.
Earlier, the offenders stole a female dog from the same property, but the teenage boys managed to get the dog back before the offenders left.
The male is perceived to be Caucasian in appearance, solid build, 174cm tall and was wearing a black face mask.
The female is described as having a slim build and was wearing a chequered red hooded top, black gloves, pants and a mask.
Investigators have released an image of the stolen Bull Arab dog, Bruiser, in the hope someone recognises him and can provide information on his whereabouts.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppervic.com.au.
