MEXICO CITY (AP) — Press groups called for justice Monday after unidentified gunmen killed a journalist in southern Mexico along with a police officer assigned to protect him after a 2016 attack.

Pablo Morrugares was the fifth journalist to be killed in Mexico this year, in attacks which are increasingly killing police guards assigned to the victims. More than 140 journalists have been killed over the past 20 years.

The prosecutors’ office in Guerrero state said Morrugares and a state police officer were at a restaurant when they were killed in a hail of bullets Sunday. Authorities found 55 shell casings from assault rifles at the scene in the city of Iguala. The killers apparently opened fire from a passing vehicle.

Morrugares was director of the P.M Noticias Guerrero web site, which frequently reports on the gang violence that plagues the region. Local media reported that threats against Morrugares had been displayed in the past on banners hung by roadsides, a tactic frequently used by drug gangs in Mexico.

On Monday, the Inter American Press Association called on authorities to investigate the crime. It said Morrugares and his wife had survived a previous attack in 2016, when attackers opened fire on their car. The group called on Mexican authorities to provide better funding and protection for journalists registered in a government protection program.

While the Mexican government has sometimes assigned police bodyguards for threatened journalists, killers have increasingly been murdering both the journalists and their guards.

In May, gunmen killed the owner of a newspaper and one of the policemen who had been assigned to protect him in northern Sonora state, following earlier threats.