Colleagues at UBS AG called Kweku Adoboli, the trader arrested in connected with a $2 billion loss due to unauthorized trading at the bank, up and coming and someone who worked hard...played quite hard too.

Adoboli, 31, was arrested on Thursday by London police on suspicion of fraud by abuse of position, and is being held in custody at Bishopsgate police station. Born in Ghana, this graduate of Nottingham University studied computer science in college and went to work at UBS in London in 2006.

According to the Financial Times, a former colleague of Adoboli's who worked in UBS' London-based exchange and sat near the trader said Adoboli was well regarded by fellow workers.

He came across as someone who worked quite hard to get where he was and played quite hard too, the acquaintance told the Financial Times. There is a lot of shock, horror and disbelief. He was incredibly straight and upstanding with very high integrity. He would definitely not be the first place you start looking.

But over the past month, as global financial markets from the U.S. to Europe rocked among concerns over government debts and slow-growth economies, Adoboli reportedly shared with others concerns through social media posts.

Can we shut down global markets for a week so everyone can just chill out? Adoboli wrote in one social network post.

A former landlord said Adoboli is a well-dressed quiet man of African origin who wasn't the tidiest but was very well spoken.

Philip Octave, Adoboli's former landlord, told The Associated Press the UBS employee charged in the rogue trading scheme which rocked the Swiss bank, possibly causing the entire company a third-quarter loss, that Adoboli fell behind in his rent a couple of times but always paid up in the end.

Octave said Adoboli's rent was $6,320 before the investment banker moved out.

He was not a party chap, Octave told The AP. I found no problems.

UBS has not confirmed the name of the trader accused of losing nearly $2 billion in unauthorized trading, but London police said they arrested a 31-year-old man Thursday on suspicion of fraud by abuse of position for the UBS rogue trading disaster, and that the man remains in custody.They have confirmed the man charged is Adoboli.

According to a Facebook profile now removed, Adoboli lists UBS as a network, and among Activities and Interests lists among many favorites, Al Jazeera English, Ghana, I'm a Photographer, Not a Terrorist!, Samjhana Moon - Photographer, Wani Olatunde Photography, Brother Mouzone (The Wire), and Vines of Argentina.

Adoboli listed his home as London, United Kingdom, and has 417 Facebook Friends, though the number was 420 early Thursday morning. By mid-morning Thursday, Adoboli's Facebook page was deleted.

Adoboli also listed among favorites a London pub, Boundary - Restaurant, Rooms & Suites, Rooftop.

The Swiss bank's loss is a staggering demonstration that all the clever systems that the banks now have, especially after the financial crisis, still cannot stop a determined individual getting round them if they want to, Chris Roebuck, visiting professor at Cass Business School in London, told Reuters.

Meanwhile, the news caused UBS stock to take a beating in trading on the Zurich Exchange Thursday. Stock shares dropped as much as 10 percent as markets were stunned with the company's admission that a rogue trader cost the company as much as $2 billion and that the bank will likely post a third quarter net loss after the episode.

UBS issued a short confessional of the rogue trading loss before European markets opened, explaining to investors that UBS has discovered a loss due to unauthorized trading by a trader in its investment bank. UBS employees about 18,000 in its investment bank, and most are based outside of Swizterland, working primarily in London and the U.S.

The bank also sent a letter to employees, attempting to calm shaken nerves about the bank's solvency amid the rogue trading loss.

Although the news is regrettable, the fundamental strengths of the company won't be affected by this, the note said. We ask that you continue concentrating on your customers. In these uncertain times they are counting on your support.

UBS says no client positions were affected by unauthorized trading, but the blow will be significant -- and some suggest it could threaten the future of UBS' investment bank, already suffering from reputation blows after massive sub-prime losses during the financial crisis, resulting in government bailout.

UBS suffered an embarrassing U.S. tax evasion case last year that exposed Swiss banking secrecy.