Human bones found close to Harry and Meghan's California mansion

Human remains have been found close to Prince Harry and Meghan Markle's multimillion-dollar Californian mansion.

The couple bought the house last summer when they moved to the city of Santa Barbara, also home to the likes of Orlando Bloom, Ellen DeGeneres and Rob Lowe.

The Santa Barbara sheriff's office said the remains were found on a road in Montecito, reportedly close to the royals' home.

The office's spokeswoman Raquel Zick said the remains were "partial" and appear to be of a "small-sized adult", and suggested they date back many years.

The Santa Barbara Independent reported that the remains were found on 25 May at around 5.15pm local time during building work on an estate. The work stopped immediately.

An investigation has been opened and Zick said a forensic anthropologist would be assessing the bones.

Zick did not confirm the exact site of the discovery but did tell the Independent: "We’re only confirming it was on the 800 block and that it’s not associated with the royals."

Watch: Will he do it? Over 43,000 people sign petition requesting Prince Harry give up his royal titles

Read more: Duchess of Cambridge is a 'peacemaker' says her uncle

Early speculation suggests the bones could be linked to the Chumash people, and if that is the case, they will be turned over to the Native American Council.

The Chumash inhabited central and southern coastal parts of California but lost much of their land during the 1800s. There is now a reservation, but the last speaker of their language died in 1965.

In April it was revealed that police had been called to Harry and Meghan's home nine times in as many months for issues including "alarm activations". At least one was a phone request.

The couple, who live in the mansion with their two-year-old son Archie, called officers on Christmas Eve after a man was alleged to be trespassing.

And on Boxing Day they were back for an incident listed as "property crimes".

Harry and Meghan are expecting their second child, a daughter, this summer, though they have not been more specific about the due date.

Watch: Oprah gives her take on Prince Harry's relationship with his family