LA MORA, Mexico (CNN) — A relative of U.S. citizens killed in a massacre in northern Mexico met Monday with the country's president and said the family was "pleased with advances made in the investigation."

Adrián LeBaron made the remark a day after the Mexican Attorney General's Office said in a news release that more suspects were arrested.

LeBaron and other family members met with President Andrés Manuel López Obrador, and later said "it was dangerous" for him to say much more. They will meet again with the president next month.

A person suspected of participating in the killings who was arrested in November led to "fundamental information and evidence" in the case, according to Sunday's news release from the attorney general's office. Several individuals were arrested, the news release said, offering no other details on those taken into custody.

In a separate incident Saturday, 22 people were killed in a gun battle between security forces and suspected cartel members in the northern Mexican state of Coahuila, according to a statement from the Coahuila government. The statement said "16 criminals" were killed along with four police officers and two unarmed civilians.

In the early November killings, three women and six children from the LeBaron family were gunned down while driving in three cars on a remote dirt road south of the U.S.-Mexico border.

The arrests on Sunday were made during a joint operation by the Mexican armed forces, police, the National Guard and the National Intelligence Center, the office said in the release.

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The eight children, some mere infants, who survived the ambush in northern Mexico not only escaped the drug cartel gunmen who killed their mothers but managed to hide in the brush, with some walking miles to get help despite grisly bullet wounds.

"As it is known, and in line with agreements and cooperation requested managed by the foreign ministry, members of the FBI, alongside employees and agents from the Federal Ministerial Police from the Federal Attorney General, have participated in the inquiries," the release said.

Victims of the killings

Last month, officials and family members said they believed the vehicles were targeted by Mexican drug cartels. Mexican Security Minister Alfonso Durazo said the attack could have been a case of mistaken identity of "conflicting groups in the area."

The victims, all of whom had dual U.S.-Mexican citizenship, were "all shot while in vehicles while driving," family member Alex LeBaron had told CNN.

"Women and children (between 14 years old and 10 months) were massacred, burned alive," LeBaron said. "Mothers were screaming for the fire to stop."

The victims lived about 70 miles south of Douglas, Arizona, in La Mora, founded decades ago by an offshoot of The Church of Jesus Christ of Latter-day Saints. Many La Mora residents call themselves Mormons but are not affiliated with the church.

The family has been the victim of drug cartel violence in Mexico before.

In 2009, Eric LeBaron was kidnapped and returned unharmed a week later, as CNN reported at the time. Afterward, his older brother Benjamin became a nationally known anti-crime activist who pushed the local community to take a stand against violence.

Two months later, Benjamin LeBaron, 32, and his brother-in-law Luis Widmar were beaten and shot to death after armed men stormed their home in Chihuahua. Authorities later arrested the alleged ringleader of a drug trafficking family that ran a smuggling operation on Mexico's border with Texas.

Contributing: The Associated Press

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