ROUND ROCK, Ariz. ? Tribal police have arrested six people after four victims were found, buried in shallow graves.

Dead are David K. Begay, 47 of Round Rock, Gesbert Sam 30, Pinon, and Alice Slim and her 9-year-old granddaughter from Fort Defiance.

Begay and Sam were found in a shallow grave along U.S. 191 on Nov. 3 after their vehicle was carjacked. Slim and her granddaughter were found on Nov. 5 near Tsaile, 25 miles from the location of the first bodies.

Slim and her granddaughter were believed to have been stabbed to death on Oct. 28 and Begay and Sam are believed to have been killed around Aug. 19.

Authorities said Slim’s pickup was stolen and used in an Oct. 31 armed robbery in Red Valley.

The nearby Red Rock Day School was evacuated because of the robbery. The pickup was later found along Navajo Route 12 after thieves tried unsuccessfully to burn it.

After the grizzly discovery of the four bodies, the Navajo Strategic Reaction Team was called in and surrounded the Round Rock residences of six suspects. Teddy Orsinger, 35, Gregory Nakai, 18, and Jimmy Naki Jr., 23, were arrested and charged with aggravated battery. Lezond Charles Mitchell, 20, and Orsinger’s son and a second juvenile were arrested in the investigation of the armed robbery. The juveniles’ names are not being released.

Police are seeking a seventh suspect, Denive Leal, on charges, which include aggravated battery.

Navajo Police are recommending federal charges be filed.