After Michael Usry’s DNA sample was seized by police from Ancestry.com, his son became a suspect in a murder case.

SAN FRANCISCO — Investigators are broadening their DNA searches beyond government databases and demanding genetic information from companies that do ancestry research for their customers.

Ancestry.com and competitor 23andme report a total of five requests from law agencies for the genetic material of six individuals in their growing databases of hundreds of thousands. The companies say law enforcement demands for genetic information are rare.

But privacy advocates and experts are concerned that genetic information turned over for medical, family history research or other highly personal reasons could be misused by investigators.

“There will be more requests as time goes on and the technology evolves,” said New York University law professor Erin Murphy.

Ancestry.com and 23andme officials say their databases won’t be useful to most criminal investigations because they analyze regions of DNA different from the locations forensic experts explore. Still, that hasn’t stopped investigators stumped on cold cases from contacting the companies for help.

In the summer of 2014, court documents show, the Idaho Falls Police Department obtained a warrant to seize genetic information from Ancestry.com in connection with the 1996 rape and murder of Angie Dodge.

In 1998, Christopher Tapp was sentenced to life in prison for Dodge’s murder and rape, but he’s appealing his conviction saying his confession was coerced.

Idaho Falls police sent a DNA sample found on Dodge’s body to Ancestry.com in 2014 to process.

The results established a close match. Believing the killer could be a relative of the DNA donor, police obtained a warrant to compel the company to turn over the donor’s name.

The donor was Michael Usry Sr., a contractor living near Jackson, Mississippi.

Ten years earlier, Usry donated his DNA to a nonprofit scientific organization conducting a hereditary study.

The Sorenson Molecular Genealogy Foundation had amassed more than 100,000 samples when Ancestry acquired the database in 2007.

Usry was not the right age for the 20-something suspect investigators were seeking. But his son was the approximate age and had connections to the Idaho Falls area.

Police showed up at Michael Usry Jr.’s doorstep in New Orleans in December 2014, armed with a warrant for his DNA.

The younger Usry, a filmmaker, was interrogated for six hours and finally gave blood for a DNA sample. For the next month, he remained under suspicion until his DNA was determined not to match the samples taken from the crime scene.