The group of experts probing the 2014 disappearance of 43 students in Mexico's southwestern Guerrero state will end their investigation at the end of April. Mexico's government has opted not to renew their mandate.
The head of the Inter-American Commission on Human Rights (IACHR) said Friday that the investigators were forced to cease their mission, despite unanswered questions about the fate of the students.
The IACHR "deeply regrets that the Mexican state has expressed its position not to extend the mandate of the group of experts and to end the agreement, even though the objectives - primarily, locating the missing students - have not yet been met," said IACHR chief James Cavallaro.
The independent investigators are expected to present their findings on April 24.
Official version rejected
The 43 students from a teacher-training college disappeared in the city of Iguala on September 26, 2014. Mexican authorities allege the students were detained by local police who handed them over to a drug cartel. Members of the gang then allegedly killed the students and incinerated their bodies at a rubbish dump in the nearby town of Cocula.
However, that version of events has been rejected by both the IACHR group of experts and another investigative body that analyzed the dump site. To date, the remains of only one of the students have been positively identified by burned bone fragments.
The Mexican government's own inquiry into the students' disappearance has been heavily criticized by both the victims' families and the IACHR.
New evidence revealed this week suggested federal police agents may be implicated in the students' disappearance
Search for answers
The rights commission has repeatedly called on Mexico to allow the experts' mission to continue after its April 30 expiry date. In a statement, Mexico's Foreign Ministry said it was committed to seeking justice in the case and will continue working to implement the group's recommendations.
Cavallaro said the IACHR planned to set up another body to monitor the case of the missing students beyond April. However, the body's executive secretary, Emilio Alvarez, said "the group's presence generated a unique and novel cooperation that is now going to diminish."
"But in the end, the investigation to clear up the case is the responsibility of the Mexican state," Alvarez added. "Not that of the [commission] nor the experts."
nm/cmk (AFP, AP, dpa)