The U.S. Food and Drug Administration on Wednesday sent a warning letter to Abbott, charging the Chicago-based medical device provider with failing to reveal a deadly defect with defibrillators marketed by St. Jude Medical. Abbott acquired St. Jude Medical in January, inheriting the damning issues tied to the devices.

In the letter, the FDA found St. Jude downplayed the battery failure in some of its defibrillators, and continued to ship the devices despite issues with rapid battery depletion.

St. Jude also failed to inform management and a medical advisory board about the battery issues, which led to the death of a patient, the letter read. St. Jude failed to disclose this death to the FDA.

[Also: St. Jude admits security vulnerabilities in cardiac devices]

The investigation of the incident in was completed in August 2014, and St. Jude said the cause could not be determined. However, the FDA said in its letter that St. Jude received evidence from its lithium suppliers that pointed to battery issues as the cause of death.

The company finally recalled the devices in question last fall, following another warning from the FDA. But St. Jude let seven patients receive these defibrillators in late October 2016 -- after the recall. And 10 more of the faulty devices were sent to company field representatives.

St. Jude admitted in October that two patients died as a result of premature battery depletion and 10 others fainted. But three months later the company continued to insist there were no serious deaths or injuries as a result of battery failures.

[Also: St. Jude heart device security under fire again]

In September, the company told its patients with affected defibrillators to register with St. Jude’s MerlinHome Monitoring System, but that platform was riddled with cybersecurity flaws.

Again, St. Jude denied these claims made by short seller Muddy Waters and Med Sec. St. Jude later admitted the devices were flawed -- only after filing a defamation lawsuit against the two companies.

The first Med Sec report claimed successful hacking attempts against these devices could drain battery life or manipulate a pacemaker’s beat rates. St. Jude’s stocks drastically fell as a result, but a second report released during trial reiterated these claims.

The company admitted the flaws in January, shortly after it was acquired by Abbott.

This new FDA warning sent shares of Abbott down 2 percent to $42.61 on Thursday. Abbott has 15 days to respond to the letter. If the company doesn’t correct the violations, the FDA could serve the company with an injunction, seizure or monetary fine.

“We take these matters seriously, continue to make progress on our corrective actions, will closely review FDA’s warning letter, and are committed to fully addressing FDA’s concerns,” Abbott officials said in a statement.

Twitter: @JessiefDavis