The Mexican army's Chief of Staff, Brig. Gen. Homero Mendoza Ruiz told the media on Thursday that as initially suspected, Monday's bloodbath was connected to events hours earlier in Agua Prieta, a town on the US border where at least one person died in a pre-dawn clash between the La Linea and Los Salazar groups, Efe news reported.
La Linea is thought to be a offshoot of the Juarez drug cartel, while Los Salazar may have links to the powerful Sinaloa cartel, whose founder, Joaquin "El Chapo" Guzman, is currently serving a life sentence in an American prison.
The victims were said to be members of the LeBaron family, linked to a breakaway Mormon community which settled in Mexico several decades ago.
"It is assumed that the criminal organization La Linea, in the face of Los Salazar's intention to move into Chihuahua (state), decided to send a cell between Janos (Chihuahua) and Bavispe (Sonora state)," Mendoza Ruiz said a day after travelling to the crime scene with Foreign Secretary Marcelo Ebrard and Navy Secretary Jose Rafael Ojeda.
La Linea's decision to deploy gunmen to block the move by Los Salazar may have caused the tragedy, given that the Mormons were on the road in the area at the time.
The Mormons, all members of the same extended family, were traveling in SUVs - commonly used by cartel gunmen - and La Linea could have mistaken them for Los Salazar, Mendoza Ruiz said.
Three women and six children were killed, while six other kids were injured. One child emerged unharmed and another initially feared abducted was later found.
We are "attributing the implementation of the attack against the LeBaron and Langford families" to La Linea, Mendoza Ruiz said.
The attack began on Monday afternoon on a highway running parallel to the US border as the three women and 14 children were travelling from the La Mora ranch in Sonora to Janos, Chihuahua.
Upon learning of the massacre, US President Donald Trump on Tuesday offered his Mexican counterpart Andres Manuel Lopez Obrador military assistance in fighting Mexico's drug cartels.
Lopez Obrador said that Mexico had to address the problem "in an independent manner", while welcoming cooperation "within the framework of current law and bilateral agreements".
Because all of the victims had dual US-Mexican citizenship, Mexico will keep US authorities apprised of progress in the investigation.
( With inputs from IANS )