At a Massachusetts sports agency, attorney Derege Demissie has built a practice representing marathon runners. Now the Ethiopian immigrant has taken up another job—as counsel to a man who allegedly aided Boston Marathon bombing suspect Dzhokhar Tsarnaev.

Demissie, an attorney at Apex Athletics Agency in Cambridge, Mass., on Wednesday made his first court appearance in Boston’s U.S. district courthouse on behalf of Tsarnaev friend Robel Phillipos. Investigators said Phillipos initially lied about visiting Tsarnaev’s college dorm room on the night of April 18, three days after the bombing.

"He made a misrepresentation," Demissie said of his client during a brief interview outside the courtroom. Demissie, also listed as an attorney at Demissie & Church, which uses the same address as Apex, didn’t respond to a request for further comment.

Two other defense lawyers on Wednesday made appearances in connection with the bombing. Westfield, N.J., attorney Robert Stahl and New York attorney Harlan Protass accompanied two other Tsarnaev friends who are accused of intentionally obstructing the bombing investigation by trying to dispose of evidence.

Stahl, managing partner of The Law Offices of Robert G. Stahl, represents Dias Kadyrbayev, whom "absolutely denies the charges," Stahl said on Wednesday. Protass, a Clayman & Rosenberg partner and Benjamin N. Cardozo School of Law adjunct professor, is counsel to Azamat Tazhayakov. He said the client was "cooperating fully and looks forward to the truth coming out in this case."

Protass declined to comment further on Thursday. Stahl said he was committed to fighting the charges against his client.

Stahl, who specializes in complex civil, criminal and custody matters, said his background working for clients from Russia and the former Soviet republics led him to this case. He declined to elaborate. Kadyrbayev and Tazhayakov are Kazakh nationals who were in the United States on student visas. They both were arrested on April 20 for alleged immigration violations.

A former assistant U.S. attorney in New Jersey, Stahl is no stranger to high-profile work. Among his past clients was a rabbi in a money-laundering case that made national headlines. The rabbi, Saul Kassin, pleaded guilty in 2011 in New Jersey federal court for his part in a scheme that led to 44 arrests in 2009.

Protass has been in the media spotlight, too, having contributed to Slate and The National Law Journal, among other publications. Protass, who focuses on government enforcement proceedings and criminal defense, most recently wrote in the May 21, 2012, edition of the NLJ about plea bargaining.

As for the prosecutors handling the cases against Tsarnaev’s friends, the U.S. attorney’s office in Boston tapped some of its top national security lawyers. They include William Weinreb, Stephanie Siegmann and John Capin, who have worked together on other significant homeland security cases, according to U.S. Justice Department records.

Capin and Siegmann, both in the office’s anti-terrorism and national security unit, won convictions in 2011 against Chitron Electronics Inc. and owners Zhen Zhou Wu and Yufeng Wei on charges they exported military components and sensitive electronics to the People’s Republic of China for more than 10 years.

An adjunct professor at Suffolk University Law School in Boston, her alma mater, Siegmann, was given a top prosecutor award in 2011 by the Women in Federal Law Enforcement Foundation for her role in those prosecutions.

Siegmann and Weinreb, also assigned to the case of Tsarnaev, are prosecuting Qiang Hu, a Chinese national in Massachusetts charged in 2012 with violating U.S. export laws by supplying U.S.-origin parts to end-users in China.

Siegmann was one of two prosecutors in the case of Rezwan Ferdaus, a U.S. citizen who pleaded guilty in 2012 in a plot to damage or destroy the Pentagon and U.S. Capitol using large, remote-controlled aircraft filled with C-4 plastic explosive.

She was part of the team that secured convictions in 2008 against three men—one from Libya and two from Lebanon—who were officers in a Muslim charity, Care International. The men, Emadeddin Muntasser, Samir Almonla and Muhamed Mubayyid, were convicted on charges that they solicited and obtained tax-deductible donations to support and promote terrorism.

Contact Andrew Ramonas at aramonas@alm.com. Todd Ruger can be contacted at truger@alm.com.