Jack O'Sullivan: Why missing student's brother visits last known route daily

For 10 weeks, Ben O'Sullivan's days have been spent visiting a Bristol flyover looking for his brother.

Jack hasn't been seen since 2 March, when he was pictured walking across a grassy area near Brunel Lock Way in the Hotwells area.

Ben's trying to imagine what Jack, who's four years younger, might have been doing and where he might have gone after leaving a party in the early hours.

"We know he went to a pub in town and then went on with a few friends to house party in Hotwells," Ben, 27, tells BBC Newsbeat.

"There's been a lot of unanswered questions since then.

"But going down there has provided us a way of trying to get to the bottom of everything.

"So this has become a daily routine almost."

The last confirmed sighting of the 23-year-old student was at 03:13 GMT.

But a couple of weeks ago, there was a possible breakthrough when CCTV picked up a figure walking over Plimsoll Bridge about 10 minutes later.

Then, again, walking along Bennett Way at 03:38.

Avon and Somerset Police told Newsbeat these were "likely sightings of Jack".

Evidence from Jack's phone reveals he tried to call a friend who was still at the party at 03:24, about the time he's believed to have been on the bridge.

Ten minutes later, the friend called back but the call was disconnected before Jack had said more than "hello".

Jack had been living at home with his parents who noticed he wasn't home by 05:00, even though he'd messaged them around 01:00 with plans to get a taxi.

His phone remained active on the Find My Friends app until 06:44.

"It was just very, very out of character," says Ben, who describes his brother as a "very smart, loving individual".

"He's a best friend of mine, not just a brother."

Immediately, the family sensed something was wrong. Before they called the police, Ben came from his home in nearby Clifton, asking people living near the party to check their doorbell cameras for any sightings.

"Ever since then it's been every day," he says.

"It's been very, very tough just trying to piece together information."

Sunday was one of the toughest days so far when Ben's club, Arsenal, took on Jack's beloved Manchester United in the Premier League.

"We'd always be watching that game together," says Ben.

"And for the first time not being able to do that, it was strange.

"That really hit home."

It's made him more determined than ever to get answers, continuing his daily ritual of trying to trace Jack's steps that night.

"It's so surreal," says Ben.

"It's like a puzzle but having your brother at the forefront of it, it's horrifying.

"But I'm determined, my family's determined, to get the answers that we need."

Avon and Somerset Police told Newsbeat its officers had recently reviewed more than 100 hours of CCTV, sent specialist dive teams to comb the River Avon and dog teams to to search the local area.

"We're still asking for the public's help in reviewing and supplying us with any relevant CCTV, vehicle dashcam, doorbell or mobile phone footage," Det Insp Jason Chidgey added.

Officers are particularly focusing on Brunel Way, Brunel Lock Road, Junction Swing Bridge, Plimsoll Swing Bridge and the Portway.

When Ben's been to the Bennett Way flyover, he imagines all the drivers that might have seen his younger brother above the busy road.

Police have told him "around about 400 vehicles" would have passed underneath in the time period of the last sightings.

"So we're really just trying to appeal to anyone... Any little bit of information could be really useful," he says.

Det Insp Chidgey says Jack's family is going through "an unimaginable ordeal" and officers are committed to supporting them.

Detectives are getting help from independent experts too, he adds, to "try and identify any lines of inquiry we still need to progress".

For Ben, while the family waits for more information about what happened to Jack that night, the "theories and potential outcomes are endless".

"It's hard to come to terms with it just because of what's outstanding," he says.

"Until we have concrete answers, no potential option is out of the question.

"The hope comes from the fact that this is very open-ended and until things are closed off, we're not going to let it rest."

Listen to Newsbeat live at 12:45 and 17:45 weekdays - or listen back here.