In 2018, Taylor Swift found herself at the center of one man’s disturbing and increasingly dangerous delusions.

After Swift’s former record label, Big Machine Label Group, reported receiving dozens of letters making violent and unhinged demands of the musician, Eric Swarbrick, their 26-year-old author, pleaded guilty to stalking and sending communications with the intent to threaten. Now his brother, Matthew Swarbrick, has come forward to peel back the layers of his sibling’s unsettling crimes.

Speaking on “Stalking the Stars,” the latest episode of Investigation Discovery docuseries Hollywood Demons (out April 28), Matthew says, “My brother believed Taylor Swift was his soulmate, and it got out of hand. He wrote 40 letters to Taylor Swift back in 2018. The first one is not threatening, just strange.”

But as time went by, Eric’s letters grew more outlandish, more sexually suggestive, and more violent. “Just a few months later,’ Matthew notes, “one of them references, ‘I’ll have one goal in mind, to push Taylor to kill herself for knowingly abandoning me to my mother.'”

Entertainment Weekly has reached out to a rep for Swift for comment.

“In my family, growing up, Eric spent a lot of time with friends,” Matthew recalled. In high school, he noted that Eric was “popular, he led worship, he played guitar, he was very outgoing. I didn’t see any signs at all in Eric. There was nothing that was a red flag.”

But then the Austin native started college. Matthew explained that his brother “didn’t know a lot of people. I feel like he started spending more time by himself. Some of the isolation eventually got to him.”

Upon graduating, Matthew recalled “a series of tweets” sent by Eric that “[referenced] a soulmate. They did not reference anybody in particular, but it was not something that a normal person would write. It basically referenced being a prophet of God, being on the verge of becoming the Antichrist. I remember feeling very desperate because we knew he needed help and we had absolutely no idea what we could do.”

Eric’s initial letters addressed to Big Machine CEO Scott Borchetta pleaded with the executive to introduce Eric to the “Cruel Summer” singer. Then he claimed to have wandered through the label’s Nashville office in the past. Eventually, Eric’s rhetoric escalated to a level that warranted the intervention of law enforcement.

“I will not hesitate to kill her, and there’s nothing you, your lawyers, or the law will be about to do about it. Remember who I am,” one of the letters read. Another stated, “I want to rape Taylor Swift. This is why I hate Taylor herself… This is how I know I am Taylor’s soulmate.”

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Eric took to personally transporting the letters to the Big Machine office, which meant his eventual crimes were upgraded to the federal level. He was initially arrested in August 2018 after attempting to access Big Machine HQ, but was quickly released. After a third letter run in September, Eric was arrested again by national police in Travis County, Tex., and charged with interstate stalking and sending interstate communications with intent to threaten.

He pleaded guilty to the charges in 2019, and the year after, a federal judge sentenced Eric Swarbrick to 30 months in prison and three additional years of supervised release.

“I definitely didn’t know he had been visiting her office and that he wrote 40 letters,” Matthew shared.

Reflecting on learning about the extent of his brother’s deeds, Matthew stated, “It was sad, it was depressing. There are some people that need punishment and some people that need treatment. I certainly wish he was taken to a mental health hospital earlier than they did.”

After Eric was released, Matthew said that his brother began “seeing a psychiatrist and slowly he was starting to become his old self in a lot of ways.” He describes Eric in his current state as “very playful and interactive” with Matthew’s children.

While law enforcement was able to defuse this particular threat before it escalated into crisis territory, the nightmare of alleged stalking incidents hasn’t ceased for Swift.

A man named David Liddle was arrested near Swift’s Rhode Island residence in 2019 after being found with a bag containing a crowbar, aluminum baseball bat, lock picks, and rubber gloves. The same year, a man named Roger Alvarado was arrested after attempting to break into Swift’s Manhattan home for a third time. A Brooklyn man named Joshua Christian was charged with criminal trespassing and stalking Swift in 2022.

Two more men were arrested on suspicion of stalking Swift last year alone.

“You get enough stalkers trying to break into your house and you kind of start prepping for bad things,” Swift told Elle in 2019. “Every day I try to remind myself of the good in the world, the love I’ve witnessed and the faith I have in humanity. We have to live bravely in order to truly feel alive, and that means not being ruled by our greatest fears.”

“Stalking the Stars,” the last episode of Investigation Discovery’s new series Hollywood Demons, airs Monday at 9 p.m. ET/PT on ID and streams on Max.