Reports of livestock theft from Victorian farms have increased by almost 15 per cent in the past year with only a singular arrest made in the last 12 months.

Former homicide detective Sol Solomon recounts the hunt for killers in the cases that have shocked and haunted him.

Victorian farm crime investigators admit the majority of livestock thefts are going cold, urging producers to bolster on-farm security following a $100,000 double-hit in the state's west.