Requena became active in Los Angeles politics in the 1830s, during the Mexican era, and continued serving after the American Conquest of California until his death in the 1850s.

The ayuntamiento was about to accept it when someone reported that Don Manuel was engaged in pruning his vineyard, whereupon a committee of investigation was appointed, with Juan Temple, merchant, as medical expert.

The committee and the improvised doctor examined Don Manuel, and reported that his indisposition did not prevent him from pruning, but would incapacitate him from serving as a judge of the election.

In April 1836, a force of vigilantes demanded that he cooperate with them in turning over the key to a house where fugitive Maria del Rosario Villa, accused of murdering her husband, was staying.

Guinn, "the only instance in the seventy-five years of Spanish and Mexican rule in California, of the people, by popular tribunal, taking the administration of justice out of the hands of the legally constituted authorities.