Liberal watchdog groups are calling for an investigation into Rep. Ken Calvert of Inland Empire, the longest-serving Republican in California's congressional delegation.

End Citizens United, a campaign finance reform group Filed a complaint On Tuesday, the Office of Congressional Ethics alleged that Calvert failed to disclose information about various rental properties he owns in Riverside County.

The complaint follows a Times story alleging that Calvert used a legislative procedure called budget designation to secure more than $100 million in taxpayer funds for his district, including more than $16 million for transportation projects within a few miles of his rental property.

“This is a baseless complaint from a far-left super PAC supporting Ken's opponent, and even worse, it misrepresents the facts,” said Calvin Moore, a spokesman for Calvert's reelection campaign.

Questions about Mr. Calvert's real estate investments have resurfaced as the longtime congressman faces off against Democrat Will Rollins, a former federal prosecutor, in California's 47th Congressional District, which includes Corona and Palm Springs, considered one of the most competitive in the country.

The Times found that Mr. Calvert had failed to disclose the purchase of an auto repair center in Corona that he acquired in 2016. His office described the omission as a clerical error. The property is about a mile from a bridge that received $2 million in earmarked funds through Mr. Calvert's office.

Calvert's office said he and his brother bought the property in September 2016 for $2.25 million and have an 11% stake in the deal, which is valued at $247,000.

Moore said Calvert has “always done its best to be transparent in its financial disclosure statements.” Calvert filed six years of amended financial disclosure statements last week to disclose the auto repair center purchases.

The complaint filed Tuesday also alleges that Calvert failed to report the purchase of two other properties, one in Corona and one in Palm Springs. Jason Gagnon, a spokesman for Calvert's office, said one of the properties was properly reported and the other was a personal loan that Calvert reported “even though he was not required to report it.”

The Office of Congressional Ethics is an independent group without subpoena power that reviews allegations against members of Congress and potentially refers them to the House Ethics Committee for further investigation.