The mother of the Shafia family has joined her husband and son in filing her intention to appeal her convictions on four counts of first-degree murder.

Tooba Yahya, 42, her husband Mohammad Shafia, 58, and their son Hamed, 21, have now each filed an inmate notice of appeal, which is the first step toward filing a full appeal at a later date.

The three were convicted Jan. 29 of killing daughters Zainab, 19, Sahar, 17, and Geeti, 13, and the first wife in the polygamous marriage, Rona Amir Mohammad, 52.

The bodies were found June 30, 2009, in a car at the bottom of a canal in Kingston, Ont.

The judge described the killings as being motivated by the Shafias' "twisted concept of honour."

All three notices of appeal raise the same three grounds on which they're seeking to appeal, including a claim the judge shouldn't have admitted evidence from an expert on so-called honour killings.