In 1840, the Ute leader Walkara led a great raid through the Cajon Pass into Southern California to capture a large number of horses from the Mexican ranchos.
Following a dispute with the Lugo's the New Mexicans moved south to build the settlements of Agua Mansa and La Placita de Trujillo on the Rancho Jurupa.
Chief Juan Antonio was then invited to move a group of his Cahuilla Mountain Band to Politana in their place.
Juan Antonio also lent support to a U.S. Army expedition led by Lieutenant Edward Fitzgerald Beale, defending the party against attacks by Walkara and his band of Ute warriors.
In the summer of 1851, Juan Antonio and a group of his fellow tribesmen pursued and destroyed the outlaw Irving Gang in San Timoteo Canyon.
Working on the ranchos and hunting down native raiders and bandits was a role that Juan Antonio's people had played in the San Bernardino region under the Mexican authorities.