FRESNO, Calif. -

Prosecutors say a man charged with murdering nine people in California has told authorities that he has killed up to 40 people.

Errek Jett, a district attorney in Lawrence County, Alabama, said Wednesday that 51-year-old Jose Manuel Martinez told investigators he carried out the crimes working as an enforcer for a drug cartel.

Jett said they believe Martinez because of the details he gave.

Martinez was arrested last year and sent to Alabama, where he awaits trial on one murder charge. He once lived in Central California where prosecutors say he awaits nine more cases stemming from crimes committed in three counties.

He's also accused of kidnapping and committing murder for financial gain, which makes him eligible for a death sentence.

Prosecutors in California say the slayings happened over 30 years.