Mass killer Derrick Bird, who is believed to have been tipped over the edge by resentment over money he thought had been left to his brother, left behind more money in his will than his murdered twin.
David Bird, 52, was the first of the 12 victims shot dead by the taxi driver during his murderous rampage across Cumbria in June.
It was thought that Bird, 52, who committed suicide after the killings, snapped after arguing with his twin over their elderly mother Mary's will. But probate records show that the gunman left 105,000 while his brother's estate was worth only 82,000.
The twins' father Joe gave David 25,000 before his death in 1998, but Bird apparently received nothing.
The divorced father-of-two began his shooting rampage on June 2 by killing his brother and the family solicitor, Kevin Commons, 60, at their homes.
He then shot several fellow taxi drivers before blasting passers-by apparently at random, and then shot himself.