HRW: Mexico security forces colluded in disappearances21/02/2013 14:00
The group has documented almost 250 disappearances during the term of former President Felipe Calderon.
It says evidence suggests that in more than half of the cases the security forces participated either directly or indirectly in the disappearances.
HRW has called on the new government to find the missing.
In a report published on Wednesday, HRW says "state agents participated directly in the crime [of disappearances], or indirectly through support and acquiescence" in more than 140 of the cases they investigated.
In the remaining cases, their researchers were not able to determine whether state actors may have participated.
HRW says the majority of the cases of enforced disappearances it investigated followed a pattern, in which members of the security forces "arbitrarily detain individuals without arrest orders or probable cause".
"In many cases, these detentions occur in victims' homes, in front of family members; in others, they take place at security checkpoints, at workplaces, or in public venues, such as bars," the report alleges.
The report says that the administration of former President Calderon ignored the mounting problem and failed to take steps to address it, thereby contributing to it becoming "the most severe crisis of enforced disappearances in Latin America in decades".
An estimated 70,000 people are believed to have been killed in Mexico since December 2006, when Mr Calderon came to power and declared war on the country's powerful drug cartels.
Mr Calderon deployed the army in an attempt to curb the violence, but human rights groups say the levels of human rights abuses against civilians has risen as a result.
Mexico's interior ministry has not yet commented on the report.
Human Rights Watch says it hopes the administration of President Enrique Pena Nieto will develop a national strategy to tackle the growing number of disappearances.
According to HRW, the creation of a national database documenting disappearances and unidentified remains would be an invaluable tool for investigators and relatives trying to trace the missing.
Shortly after coming to office on 1 December 2012, Mr Pena Nieto announced the creation of a new national police force which he said would be better trained and better equipped to fight crime.