Drugs cartels are blamed for General Tello's murder last week
Mexican troops have detained the police chief and 36 other officers in the resort of Cancun in connection with the murder last week of an ex-army general.
Soldiers swooped on the police HQ and took police chief Francisco Velasco to Mexico City for questioning.
Former general Mauro Enrique Tello, who had just taken command of a squad to tackle crime in Cancun, was tortured and shot by suspected traffickers.
Some 5,400 people were killed in drug-related violence in Mexico in 2008.
In a surprise operation, dozens of heavily armed soldiers swarmed on the police station in the municipality of Benito Juarez, which includes Cancun.
Soldiers stripped the police chief and his officers of their weapons to check the registration of the guns.
Chief Velasco was flown to the capital for questioning in connection with Gen Tello's murder.
Gen Tello, who retired from the army earlier this year, had been sent to Cancun to lead a new force intended to break up the influence of drugs cartels.
He and two other men with him were abducted on a local main road, then driven to a remote location where they were tortured and then shot.
The BBC correspondent in Mexico, Stephen Gibbs, says the general's death, the day after he arrived to take up his new job, is being blamed squarely on corrupt police and drugs cartels.
Drug-related violence in Mexico is soaring, as criminal gangs fight both each other for control of the trafficking routes from Colombia to the US, and fight federal forces deployed against them.
Some 40,000 soldiers and police have been deployed since December 2006 against the cartels.
Much of the violence to date has been concentrated in Mexico's northern border cities, while Cancun, which attracts millions of tourists every year, has largely been spared.
Our correspondent says the general's killing is another sign that Mexico's drug war has no boundaries.