U.S. Rep. Doug Lamborn of Colorado Springs bought shares of stock in a company at the center of a recent congressional ethics investigation into possible insider trading involving one of his House colleagues.

The nonpartisan Office of Congressional Ethics recently found “substantial reason to believe” U.S. Rep. Chris Collins of New York violated federal law and House ethics rules by sharing nonpublic information regarding an Australian biotech company, Innate Immunotherapeutics.

The investigation showed that Collins, who is Innate’s largest shareholder, touted the company to members of Congress and other investors as it tested a drug to combat autoimmune diseases such as multiple sclerosis. He also discussed the drug development in a 2013 meeting with the National Institutes of Health.

Lamborn and his wife bought stock in the company in 2016 and again in 2017. Financial disclosures show the couple currently owns between $30,000 and $102,000 of Innate stock.

But the six-term congressman is refusing to answer questions from The Denver Post about his stock purchases, declining multiple interview requests through a spokesman.

His office also did not respond to written questions sent last week about whether Collins tipped Lamborn to the stock and shared inside information before the purchase.

The House Ethics Committee, upon receiving the report Oct. 12, announced it would continue to review the matter. Collins denied any wrongdoing. Lamborn was not directly named in the ethics report.

The committee has the power to launch formal investigations, subpoena witnesses and recommend sanctions, though the latter is rare. U.S. Rep. Jared Polis, D-Boulder, is a member of the committee.

It is unclear if Lamborn was contacted by the congressional ethics office as part of the Collins probe. Lamborn spokesman Dean Miller said the Colorado lawmaker is not under investigation.

Lamborn and his wife made their largest purchase of Innate stock Jan. 24 — just as the company was coming under intense scrutiny.

The same day, then-U.S. Rep. Tom Price of Georgia faced pointed questions from Democrats in his Senate confirmation hearing for Health and Human Service secretary regarding stock trades of Innate Immunotherapeutics. Price’s critics suggested the purchases amounted to conflicts of interest because the company could have benefited from his legislative actions.

Politico first reported the timing of Lamborn’s purchase and noted that three other congressmen bought Innate stock days later.

In an emailed statement, Lamborn’s spokesman acknowledged the purchase came as the company entered the spotlight but did not elaborate. Miller said the congressman “purchased the stock on the open market, at fair market value, following news media discussion about the company,” adding that he has “not made money on this investment.”

The ethics investigation comes at a precipitous time for Lamborn. Four fellow Republicans are now challenging him in the party’s 2018 primary, including state Sen. Owen Hill and El Paso County Commissioner and unsuccessful U.S. Senate candidate Darryl Glenn.