A San Marcos SWAT standoff unfolded Saturday after a man shot and killed his mom's pet turtle and began threatening her, San Diego Sheriff's deputies (SDSO) confirmed to NBC 7 San Diego.

The incident began at 10 a.m. at a senior mobile home park on the 3500 block of Linda Vista Drive near Rancho Vallecita when the man, identified as 27-year-old David Nelson, killed his mom's tiny pet turtle and threatened her.

When he began to threaten his mom, Kerry McCuin, she saw something black in his hand and thought he had a gun. McCuin managed to get out of the house, where she called 911 to say her son had shot and killed her pet turtle. She told officials her son had said he wanted to become famous for killing people, deputies said.

When deputies arrived, they tried to establish communication with him, but Nelson barricaded himself in the home. He would not reply to deputies. The SDSO's Special Enforcement Detail (SED) and Crisis Negotiation Team (CNT) were called to assist, but he would not leave the house. The Sheriff's helicopter, ASTREA, flew overhead for a period of time, asking the suspect to surrender.

Deputies feared he may have been armed and evacuated nearby homes. Some roads in the area were closed as they worked.

Eventually, deputies called in SWAT at around 2 p.m. SED officials used chemical agents to "flush Nelson out of the resident", and he surrendered when he stepped out of the house.

When he left the house, he was not armed, deputies said. It is unclear if he was armed earlier in the day or if he had a weapon. No one was hurt during the incident.

Deputies said they have been to the house before and are familiar with Nelson.

No further information was immediately available.