Six people were shot dead inside a private law office in central Mexico, state prosecutors said.
Five men and a woman were killed in Thursday's attack in the city of Guadalajara, the Jalisco state attorney general's office said in a statement. It was not immediately clear whether they were lawyers.
Two women survived the shooting, the statement said. Mexico City newspaper El Universal reported they were seriously wounded, citing unspecified police reports.
The bodies were found in different parts of the office, and some of the victims' hands were tied, the statement said. The gunshot wounds appeared to come from a 9 mm weapon.
No arrests had been made, and authorities did not say whether anything appeared to have been stolen.
In recent years, Mexico has suffered a wave of organized crime and drug-related violence that killed more than 2,500 people last year alone.
It was not immediately clear if the office had clients with links to organized crime.
33 bodies found at house
Mexican investigators also found 19 more bodies buried in the backyard of a house in Ciudad Juarez, across the border from El Paso, Texas, increasing the tally of corpses found there to 33, officials said Thursday.
Federal agents began digging in the yard in the La Cuesta neighborhood on March 1, initially finding six dismembered bodies, Mexico's federal attorney general's office said in a statement.
The attorney general's office did not say how the victims died or who may have buried the bodies. In the initial raid, authorities found 3,740 pounds of marijuana in the house.
Ciudad Juarez has been plagued by violence as Mexico's crackdown on powerful drug cartels stokes turf wars among traffickers that have been linked to hundreds of killings in the past two years.
Cartels frequently use "safe houses" in border cities to store drugs, house gunmen and dispose of dead rivals.