Amnesty International says the number of unsolved disappearances in Mexico constitutes "a national scandal and a human rights crisis."

Amnesty's Mexico investigator says authorities systematically fail to investigate disappearances, forcing relatives to investigate for themselves.

Rupert Knox says police and prosecutors often don't even bother to use the information that relatives dig up.

Knox noted Tuesday that Mexico's government has created a special investigative unit. But he says such agencies have been formed in the past merely to placate the public.

The government says more than 26,000 people have been reported missing since 2006, when Mexico launched an offensives against drug cartels.

On Tuesday, sobbing relatives related stories of police who did nothing to investigate their cases, even after being offered names or descriptions of suspects.