The National Football League has launched an inquiry into alleged locker-room bullying at the Miami Dolphins, including claims that one junior player was racially abused and that lower-paid newcomers were expected to finance the expensive luxury lifestyles of multi-millionaire teammates.

Club officials suspended Richie Incognito, a senior offensive guard, for “conduct detrimental to the team” after receiving a formal complaint from representatives of Jonathan Martin, a young player who walked out during a training session a week ago and who has not returned to Miami since.

Incognito, a self-described “wild child” on his Twitter profile, is alleged to have sent Martin a series of threatening text messages and at least one voicemail in which he called Martin a "half nigger", according to ESPN. They added that the “intimidation” stretched back into the 2012 season.

The wider inquiry by NFL officials is also expected to look into an alleged culture of bullying in the Dolphins locker room, especially charges that rookie players who are paid the league minimum salary of $390,000 were almost bankrupted by the financial burden imposed on them by veteran players.

One of the reported claims against Incognito, which he has denied, is that he pressured Martin, a left tackle in his second year with the Dolphins, to pay $15,000 towards an unofficial players’ trip to Las Vegas that he did not attend.

Meanwhile, another senior Dolphins player posted on Twitter a photograph of teammates enjoying a lavish seafood dinner with the caption: “Everything tastes better when rookies pay for it.”

Everything tastes better when rookies pay for it pic.twitter.com/KGaisEfap2 — Jared Odrick (@JaredOdrick98) November 2, 2013

A colleague tweeted that he had seen a dinner bill for $30,000, which the junior players were expected to pay, prompting one anonymous participant to tell the Miami Herald that several seniors on the team used their rookie colleagues as their “personal ATMs”.

On Monday, a spokesman for the Dolphins referred media inquiries to the official club website, which contained a series of three statements released through the day on Sunday as events unfolded.

In the first, the club’s tone appeared defiant. The statement did say that accusations of player misconduct were always taken seriously, but it denied that the NFL Players’ Association was investigating and included a line that said: “The notion of bullying is based on speculation and has not been presented to us as a concern from Jonathan or anyone else internally.”

Later, after Martin’s representatives filed his formal complaint, a second statement announced that an internal review would take place, and that the club had asked the NFL to “conduct an objective and thorough review.”

“As an organisation, we are committed to a culture of team-first accountability and respect for one another,” it said.

Finally, the club announced its indefinite suspension of Incognito, a decision it said it believed was: “in the best interest of the organisation at this time”.

Incognito, 30, is in the final year of a three-year, $11m contract with the Dolphins. When the allegations against him were first aired on ESPN on Sunday, he ranted on Twitter against Adam Schefter, the journalist who reported them, and dismiss the claims as “lies”.

“Stop slandering my name. You hide behind ‘sources’ who are not man enough to put their name behind the BS you report,” he wrote in one tweet. In another, he tells Schefter: “Enough is enough. If you or any of the agents you sound off for have a problem with me, you know where to find me.”

In the last message posted before just before his suspension was announced, Incognito wrote: “I want my name CLEARED.” His account has been inactive since.

On the field, Incognito’s suspension comes at a crucial time for the Dolphins, who beat Cincinnati in overtime on Halloween night to end a three-game losing streak and reach the halfway point of the season at 4–4, still with hopes of reaching the end-of-season play-offs.

Martin has told friends he plans to take a few weeks away from the club to deal with “emotional issues,” according to Fox Sports. Joe Philbin, the Dolphins head coach, and several teammates have said he would be welcomed back “with open arms”.

DeMaurice Smith, executive director of the NFL Players’ Association, said his organisation would “take a hard look, and stay on top of” Martin’s situation.

An official statement from the NFL on Sunday said the league had been talking to the Dolphins since last Monday, when Martin, 24, left the club after an alleged lunchtime prank in which a group of players stood up and walked off as he joined their table with his tray of food.

“We have been in contact with the team on this matter since last week and we will conduct a thorough review,” the statement said.