Families of WA surfers Dean Lucas and Adam Coleman reveal grief as arrests made

The families of two Australian surfers missing from Mexico have revealed their pain from not knowing the fate of their sons as local authorities arrested three men in connection with their suspected murders.

The burnt-out van of West Australian tourists Dean Lucas and Adam Coleman, both 33, was found with two unidentified bodies last month but police are still conducting DNA tests to confirm the remains.

Mr Lucas and Mr Coleman, both from Golden Bay just south of Perth, were driving in a van in the violence-plagued northwestern state of Sinaloa when they were stopped by a gang, chief state prosecutor Marco Antonio Higuera Gomez said.

The suspects, whose car flashed police-like lights to stop the van, confessed to shooting a long-haired tourist in the face when he resisted a robbery on November 21.

The robbers then killed the second man, drove the vehicle to another location and "set fire to the van with two bodies inside", Higuera told local reporters.

Families of missing WA duo speak

The families of the two tourists expressed their gratitude for the support they had received back home and overseas as they revealed the toll of "this dark episode" .

"The tragic events of the last fortnight are weighing heavily on those close to Dean and Adam and the siblings of both men request that their privacy be respected," family friend Gareth Taylor said.

The siblings of both men requested privacy over their "lost brothers" and wanted any information regarding their case to be reported to relevant Australian authorities.

Both families were grateful a strong bond was being forged by the many people who knew Mr Lucas and Mr Coleman.

"If any positives can be drawn from these sad events, it is that the vast amount of people drawn to the characters of both [men] in their lifetime, are now sharing a common bond," Mr Taylor said.

"And from that, old friends are coming together and new friendships are being forged."

Identities not confirmed

The prosecutor stressed that while the case of the Australians was being investigated as a murder, the identity of the two bodies in the van had yet to be confirmed.

Prosecutors did not say when the arrests were made but two other suspects are on the run.

"These people are part of a criminal group dedicated to vehicle thefts, drug dealing and with a history of committing murders," state prosecutor Higuera said.

Municipal and federal police uniforms were seized from the suspects, who wore them to commit highway robberies.

Mr Lucas and Mr Coleman were last seen in the Sinaloa town of Topolobampo on November 20 after arriving on a ferry from the Baja California peninsula.

The two had driven from Edmonton in Canada and across the United States to Mexico to join Mr Coleman's Mexican girlfriend Andrea Gomez in the western city of Guadalajara.

Their van was discovered on November 21 on a rural road of the town of Navolato. Last weekend authorities confirmed the vehicle belonged to the West Australians, raising fears about their fate.

Navolato mayor Miguel Calderon described the region as a "Bermuda Triangle" of crimes that include robberies, murders and kidnappings.

Money raised for duo's families

More than $60,000 was raised on the crowdfunding website www.gofundme.com to help the two men's parents travel to Mexico and find answers.

It emerged on Friday that the bodies in the van contained gunshot wounds, suggesting they were killed before being set on fire.

Girlfriends of the two men were supplying hair samples and dental records to help determine whether the bodies are those of Mr Lucas and Mr Coleman.

The two friends had been living and working in Edmonton and drove the van to Mexico for a surfing safari and to catch up with Ms Gomez.

On the night of November 20, two men who resembled Mr Lucas and Mr Coleman were seen entering an all-night convenience store in the coastal Mexican city of Los Mochis.

The men appeared to be in a hurry and were looking to buy a map, a witness said.

At 10.30am the next day, a Chevrolet van identical to the one being driven by the Australian pair was found burnt-out in farmland at Navolato, about 200km south of the convenience store they were spotted.

The area is home to the powerful Sinaloa drug cartel led by fugitive drug kingpin Joaquin "El Chapo" Guzman, who broke out of a maximum security prison in July.

While tens of thousands of Mexicans have been killed or gone missing in nearly a decade of drug violence, violent attacks on foreign tourists are less common.

- with Fairfax Media and wires