DURANGO (AFP) - Authorities arrested 158 police officers in two northern Mexican towns over alleged links to drug traffickers, forcing the army and state police to fill the security void. The army, federal and state police rounded up 110 municipal officers in the town of Lerdo and another 48 in neighboring Gomez Palacio, including their two chiefs, said Durango state attorney general Sonia de la Garza Fragoso. The army and state police had to take over security in both towns since the remaining municipal officers will undergo training and background checks to ensure that “links with criminal groups are eradicated,” her office said in a statement. The massive purge highlights the often cozy relationship between local police and drug cartels in Mexico, a country plagued by drug-related violence.