A South American person was the target of a failed explosive attack outside the offices of the National Migration Institute (INM) in Morelia on Monday, according to the Michoacán attorney general.

The explosive device didn’t detonate and was removed by explosives experts from the Michoacán Civil Guard police force at 9.24 a.m. Monday, the INM said in a statement.

The grenade was thrown toward the INM offices in the Camelinas neighborhood of Morelia, the capital of Michoacán, by a person in a vehicle, according to a preliminary report.

Michoacán Attorney General Carlos Torres Piña said that “everything indicates” that the failed attack using a “handmade” explosive device was aimed at “a South American person” who was waiting for the INM offices to open. He didn’t offer any additional information about the person who was allegedly targeted or cite any possible motive for the attack.

Morelia police chief Pablo Alarcón Olmedo said that authorities had reviewed security camera footage and obtained “important information” about the incident.

“We believe that two people are involved,” he said without offering further details.

No arrests in connection with the incident had been reported by 10 a.m. Tuesday.

The INM said that “the possible presence of an explosive device” outside the INM offices in Morelia was first reported at approximately 8:33 a.m. Monday.

It said that INM security personnel “proceeded to verify the information, cordon off the area and activate civil protection protocols,” which included reporting the presence of the explosive device via the 911 emergency telephone number.

Employees were evacuated from the INM offices and nearby streets were closed. Police and soldiers attended the scene before the explosive experts arrived shortly after 9 a.m.

Alarcón said that the leader of the Civil Guard’s explosives unit “manipulated the object and confirmed that it was an improvised, hand grenade-style explosive, which didn’t detonate.”

The INM said that an investigation is underway and expressed its willingness to fully collaborate with the relevant authorities on the matter. Torres said that the Federal Attorney General’s Office would lead the investigation.

In its statement, the INM said that “the safety of its staff and the users” of its services is a “priority.”

The National Migration Institute, part of the federal Interior Ministry, is the agency that handles immigration matters in Mexico. Among its duties is processing foreigners’ applications for residency in Mexico.

With reports from Reforma, Aristegui Noticias and El Universal