The 29-year-old arrived at Bondi police station shortly after 10.30am on Friday.
“The man will be transferred to Waverley police station, where investigations will continue,” NSW Police said in a statement.
Police did not reveal further details of the man’s identity, but multiple media outlets reported the 29-year-old was Constable Beau Lamarre.
Detectives had been looking for Lamarre following the disappearance of former Ten reporter Jesse Baird, 26, and Qantas flight attendant Luke Davies, 29, who have not been heard from since Monday.
Flight attendant Luke Davies, 29, disappeared at the same time as Baird.
Their disappearance is being treated as suspicious after possessions belonging to both men were found in a skip bin in the southern Sydney suburb of Cronulla on Wednesday.
Police have been trying to track down Const Lamarre, who previously dated Baird.
“Detectives are looking at a line of inquiry that a third person may be able to assist with the investigation,” NSW Police said in a statement eariler on Friday.
Officers executed a search warrant and “seized a number of items” from a home at Balmain, in Sydney’s inner west, about 11.30pm on Thursday.
Property records reportedly indicate the home was purchased under the name Lamarre.
Neighbours heard shouting at Baird’s Paddington home on Monday, but the incident was not reported to police until they arrived at the scene two days later.
Beau Lamarre pictured with Kiwi pop star Lorde. Lamarre often posted photos online when as a celebrity blogger he was pictured posing with dozens of A-listers including Taylor Swift, Selena Gomez, Katy Perry, Miley Cyrus and Harry Styles. Photo / via Instagram
Blood was found at the property, indicating someone had suffered a significant injury at the site, police said.
Baird’s WhatsApp account was active as late as Tuesday night, leading detectives to appeal for him to come forward if able.
“If Jesse’s seeing this, we’d ask him to contact us, as well as anyone that might know the whereabouts of Jesse,” Detective Superintendent Jodi Radmore said on Thursday.
She said investigators were open to the possibility someone else was involved in the double disappearance.
Police later said inquiries had led them to believe a third man might be able to assist with the investigation.
“Police are currently trying to locate him,” a statement said.
“Detectives will continue to look at all past relationships and associations.”
Lamarre, who up until days ago had an active social media presence, joined the police force in 2019.
Photos posted online show the former celebrity blogger posing with dozens of A-listers including Taylor Swift, Selena Gomez, Katy Perry, Miley Cyrus and Harry Styles.
During a 2014 Lady Gaga concert, Lamarre threw a note at the singer describing her as his “saviour”.
Gaga read the note aloud, which said: “Through your music, you have helped and will continue to set free many people ... Gaga, you’re not just my idol but literally my saviour.”
