As the investigation into Russia’s interference in the 2016 presidential election intensifies, the number of Trump associates recruiting personal lawyers continues to grow.

Hiring outside counsel is not an indication of wrongdoing. But the star-studded field of high-calibre lawyers taking on such work is indicative of the increasingly high stakes at play. The lawyers come from a range of backgrounds, from those with experience in the Watergate scandal to defense attorneys seasoned in representing notorious mafia families.

As the tangled web of the Russia probe grows thicker, many face potential conflicts of interest.

Alan Futerfas

Donald Trump Jr, the president’s oldest son, became the latest in the Trump orbit to recruit outside counsel after revelations he accepted a meeting with a Russian lawyer promising compromising information on Hillary Clinton from Russian government officials.

Alan Futerfas, a veteran New York City criminal defense attorney, is best known for defending clients involved with known mafia crime families. He has represented others involved in cybercrime.

Futerfas defended Nikita Kuzmin, a Moscow-based hacker who was arrested by US law enforcement during a trip to California in 2010. Kuzmin later pleaded guilty to numerous fraud charges as authorities branded him the mastermind behind the “Gozi virus”. The malware, which still exists, infected at least a million computers worldwide, including 40,000 in the US, leading to millions of dollars being stolen from banks.

A former law enforcement official with deep knowledge of the case told the Guardian Kuzmin was a “sophisticated hacker” who was “very well connected in the Russian underground”. His capture was regarded as one of the FBI’s most significant achievements that year, the former official said. The prosecution was brought by the former US attorney Preet Bharara, who like other senior government prosecutors was sacked by the Trump administration earlier in the year.

Kuzmin was released in May 2016, after cooperating extensively with US authorities. While in custody, according to court documents, he helped ensnare co-conspirators, some of whom lived in Russia and Ukraine. The former official said it was highly likely Kuzmin had since returned to hacking.

Futerfas did not respond to a request for comment on the case.

It was not the first time a Futerfas clients ended up cooperating with authorities. In July last year, Angelo Gigliotti avoided jail time by turning on a co-defendant at trial. Both had been accused of running a cocaine-dealing operation connected to the Genovese crime family from a pizzeria in Queens. Gigliotti’s co-defendant was his own father, Gregorio Gigliotti.

Marc Kasowitz

Proudly brandishing the moniker of the “toughest lawyer on Wall Street”, Kasowitz has enjoyed a long and fruitful relationship with Donald Trump, representing the president on a variety of cases over the past two decades.

During the 2016 presidential campaign, he successfully kept sealed Trump’s divorce records from his first failed marriage, which reportedly include sworn allegations of domestic violence. His firm, which specialises in financial rather than criminal law, also represented Trump during his Atlantic City bankruptcy cases and amid the fraud charges brought against Trump University by the state of New York.

Shortly after Kasowitz was hired as Trump’s counsel for the Russia investigation, the Washington Post revealed that he faced potential conflicts of interest. He also represents a Russian oligarch with close ties to the Kremlin and Russia’s largest state bank, Sberbank, in continuing litigation. Last month, the Guardian reported that Kasowitz’s firm was involved in the sale of a prestigious piece of New York real estate to Jared Kushner, Trump’s son-in-law and senior adviser. That could also become a conflict of interest as Kushner’s financial dealings come under the spotlight of the Russia inquiry.

In recent weeks, events have not gone well for Trump’s lead attorney. A report in the New York Times suggested he may have fallen out of favour with the president and could be on the verge of quitting. Then ProPublica published an investigation quoting anonymous former staff members and close friends saying Kasowitz had struggled with alcohol abuse in recent years. Kasowitz has denied the allegations. On Wednesday, he responded to an anonymous email from a member of the public calling for his resignation with a series of expletive-ridden rants. One began: “I’m on you now. You are fucking with me now Let’s see who you are Watch your back , bitch.”

Another attorney on the Trump team, Jay Sekulow, is also known as a combative and outspoken legal practitioner. Sekulow remained remarkably silent, however, after a series of Guardian revelations showed he had steered more than $60m from his Christian not-for-profit group to himself and his family and approved plans to prey on poor people to ramp up donations.

Robert Kelner

Trump’s first national security adviser, Michael Flynn, was sacked amid controversy over his interactions with the Russian ambassador, Sergey Kislyak, during the presidential transition. The former three-star general had hired Kelner long before he left the administration, according to reports. In March, the attorney offered to have Flynn testify before Congress in exchange for immunity from prosecution.

Kelner is a prominent defense lawyer specialising in campaign finance and political law. He has significant experience in counselling presidential appointees on the vetting process. Such expertise has already come in handy. Flynn was appointed to the Trump administration despite receiving payments from the Russian state-funded news channel RT in 2015 and a firm with ties to the Turkish government in 2016 – both after he retired from the army. The precise manner in which Flynn was vetted remains unclear but in March, under Kelner’s counsel, Flynn retroactively registered as a foreign agent with the US justice department.

Kelner is also a Russian speaker and studied politics and Russian studies at Stanford University.

The Washington DC-based attorney, who has also worked on behalf of the Republican National Committee, was an outspoken critic of Donald Trump during the campaign, mockingly referring to him as a “Manchurian candidate” after he secured the Republican presidential nomination.

In August last year, Kelner tweeted that Trump had “gone rogue” with his “Moscow Centre … controllers”, after the then presidential nominee issued a non-specific apology on the campaign trail.

“Moscow Centre trying hard to re-establish radio contact with Trump’s controllers tonight,” Kelner wrote. “His quasi-apology suggests he’s gone rogue.”

Richard Cullen

Vice-President Mike Pence reportedly spent several weeks interviewing candidates to represent him, eventually landing on Cullen, who served as US attorney for the eastern district of Virginia under George HW Bush and then briefly as the attorney general for the same state.

Now in private practice, Cullen is no stranger to operating during era-defining political scandals. He worked as a special counsel to a Republican senator on the intelligence committee during the Iran-Contra investigation and served on the staff of the Republican congressman M Caldwell Butler during Watergate. Butler, who sat on the House judiciary committee, played a pivotal role in the initiation of impeachment proceedings against Richard Nixon.

In a further sign of the crossing wires surrounding the Russia investigation, Cullen is a close friend of the former FBI director James Comey, whom Trump fired in May after allegedly pressuring him to end the investigation into Flynn. Comey was a partner at the law firm McGuire Woods, where Cullen is currently employed. Their tenures overlapped by three years, between 1993 and 1996, and Cullen is godfather to one of Comey’s daughters, according to the Washington Post.

Following Comey’s nomination to the FBI in 2013, Cullen said his former colleague would be a “great director”.

“There are many people in Richmond who remember him and his family fondly and are very pleased that the president has chosen him for such a vitally important position,” Cullen told the Richmond Times-Dispatch.

Abbe Lowell

Kushner, the president’s son-in-law and senior adviser, added Lowell, a renowned white collar criminal defence lawyer, to his legal team at the end of June. The appointment came after another of Kushner’s attorneys, the renowned former deputy US attorney general Jamie Gorelick, advised her client to seek independent advice because Robert Mueller, the former FBI director named special counsel, was a partner at Gorelick’s firm until he was appointed to the Russia investigation. Gorelick remains on Kushner’s team but, according to a Yahoo News report, has indicated she will drop out in the coming weeks.

Lowell is also well-versed in litigation involving political scandal. He was the chief minority counsel to House Democrats during impeachment proceedings against Bill Clinton and represents the Democratic senator Bob Menendez in a continuing corruption case.

The rest

At least four others in the Trump orbit have hired outside representation. The attorney general, Jeff Sessions, hired a longtime friend and noted conservative litigator, Charles Cooper, in June. Cooper had been under consideration to serve as solicitor general under Sessions but withdrew.

Paul Manafort, Trump’s former campaign manager, hired Reginald Brown, a Washington DC-based attorney who served in the White House counsel’s office and as a deputy counsel to former Florida governor and the Republican presidential candidate Jeb Bush.

Michael Cohen, Trump’s longstanding personal lawyer, hired former the assistant US attorney Stephen Ryan in June, around the same the time Michael Caputo, a former campaign communications adviser to Trump’s campaign, hired Dennis Vacco, a former attorney general for the state of New York.