Authorities announced Thursday the filing of felony charges against 42 people accused of obtaining auto insurance after an accident or theft, then making fraudulent claims for the loss. A four-month investigation, dubbed “Operation Insure,” was launched after law enforcement agencies and the National Insurance Crime Bureau determined that the type of fraud in which people purchase insurance policies after accidents or staged thefts is the most common type of auto insurance fraud occurring in San Diego County. Authorities fanned out over the county over the past two days, serving the defendants with letters informing them of the charges.