Donald Trump characterised Elijah Cummings’ Baltimore-based congressional district as a “rodent infested mess” where “no human” would want to live, in a now-viral tweetstorm on Saturday.

His criticism rang with a particular irony in Baltimore County, where the president’s son-in-law Jared Kushner owns more than a dozen apartment complexes that have been cited with hundreds of code violations and, critics say, provide sub-standard housing to lower income tenants.

In an interview on Saturday, Baltimore County Executive John Olszewski Jr condemned Mr Trump’s comments as “an attack on basic decency”.

“It is certainly ironic that the president’s own son-in-law was complicit in contributing to some of the neglect that the president purports to be so concerned about,” Mr Olszewski, a Democrat, added.

Kushner Companies, which started operating in Maryland in 2013, has owned almost 9,000 rental units across 17 complexes, many of them in Baltimore County, the Baltimore Sun reported earlier this year.

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The properties generate at least $90m (£72m) in revenue annually. Mr Kushner stepped down as CEO of the company in 2017, when he became a senior White House advisor.

A company spokesperson did not address questions on Sunday about whether the group agreed with Mr Trump’s characterisation of the area, but wrote: “Kushner Companies is proud to own thousands of apartments in the Baltimore area.”

In 2017, Baltimore County officials revealed that apartments owned by Kushner Cos were responsible for more than 200 code violations, all accrued in the span of the calendar year.

Repairs were made only after the county threatened fines, local officials said, and even after warnings, violations on nine properties were not addressed, resulting in monetary sanctions.

In an investigation by the New York Times and Pro Publica published earlier that year, tenants of Kushner Cos properties reported mouse infestations, mould problems and maggots.

A private investigator who looked into Mr Kusher’s property management company, Westminster Management, described them as “slumlords”.

Christine Taylor, a spokeswoman for the Kushner Cos, asserted at the time that the group was in compliance with all state and local laws.

Then-Baltimore County Executive Kevin Kamenetz said that was “a stretch of truth”.

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“We expect all landlords to comply with the code requirements that protect the health and safety of their tenants, even if the landlord’s father-in-law is president of the United States,” added Mr Kamenetz, who died in 2018.

Shannon Darrow, a programme manager at the tenant advocacy group Fair Housing Action Centre of Maryland, said on Sunday that she was “appalled” by Mr Trump’s comments about Mr Cummings’s district, which includes about half of Baltimore City, and most of the majority black sections of Baltimore County.

She added that she found Mr Trump’s attacks ironic given the legacy of Mr Kushner’s properties in the district.

“Basically, [Mr Kushner] has been creating a race to the bottom in terms of poorly maintained properties,” she said. “He’s been very, very deeply implicated.”

In the past two years, Kushner Cos and its affiliated entities have been sued multiple times by Baltimore-area residents who allege that the company has charged them excessive fees and used the threat of eviction to pressure them into paying up.

From 2013 to 2017, corporate entities associated with Kushner Cos’ apartments requested the civil arrest of 105 former tenants – the highest number among all property managers in Maryland during that period, the Baltimore Sun reported.

“It’s been our recent experience that working families have been preyed on at the benefit of Mr Kushner and his company,” Mr Olszewski said.

A group of tenants recently attempted to file a class-action lawsuit alleging unlawful rental practices by the company. But their request was denied by a Baltimore Circuit Court judge.