Edinburgh grandmother Julia Howard, 77, disappeared from the Moon Palace hotel in Cancun last year while on holiday.
Her remains were discovered six weeks later in dense jungle, and her family are convinced she was murdered.
Now her son, Henry Harvey, 53, has given a statement to the legal team representing US TV producer Bruce Beresford-Redman, whose wife Monica was found dead at the Moon Palace in April.
The American is fighting moves to extradite him from the US to face murder charges in Mexico.
Mr Harvey said: "I was able to tell Bruce's attorney about the horrendous way we were treated by the police out there.
"They always want to blame a tourist."