Mexico City (CNN) -- Unknown assailants shot and killed a mayor-elect in the central state of San Luis Potosi on Sunday, authorities said.
Edgar Morales Perez was murdered alongside his campaign manager, Juan Francisco Hernandez Colunga, who also was killed. They were in a vehicle on their way back from a party early in the morning when they were ambushed, state officials said.
Another person was with them, but was not wounded.
Morales Perez, a member of the Institutional Revolutionary Party, or PRI, was elected as mayor of Matehuala in July and was scheduled to have taken office this year.
The local PRI condemned the attack and called on authorities to investigate what happened. There were no immediate arrests.
The violence comes on the heels of another attack in the same state last week.
Authorities found an abandoned van containing 14 bodies along a highway in the state capital, which is also called San Luis Potosi, on Thursday.
The victims -- all men -- appeared to have been kidnapped and killed, said Gabriela Gonzalez Chong, a spokeswoman for San Luis Potosi state prosecutors.
She said then: "Everything points to this being an incidence of organized crime."
CNNMexico.com contributed to this report.