Nathan and Ellen Rigney were sleeping just before midnight on Monday when they heard a beeping noise coming from their baby monitor.

A man's voice came over the monitor, used sexual expletives, and then threatened to kidnap their baby, they told KPRC.

The Texas family believes their Nest-brand monitor, which connects to WiFi, was hacked and have discontinued using the system.

Nest told INSIDER it is encouraging users to set up two-factor authentication for added security and to contact them if they see anything suspicious.

A Memorial, Texas couple were given the shock of their life this week when they say they heard a man's voice coming from their baby monitor and threatening to kidnap their four-month-old son.

Nathan and Ellen Rigney told KPRC that they were sleeping just before midnight on Monday when they heard a beeping sound coming from their Nest-brand baby monitor. Their baby son Topper was asleep in his crib upstairs at the time.

Ellen said at first she thought it might be a CO2 alert, but then a man's voice came over the monitor.

"Then we heard sexual expletives being said in his room," Ellen said. "Immediate reaction was that there's somebody in here, somebody's in my son's room! How did they get in there?!"

They said they turned on the lights and the man ordered them to shut them off.

"Then [he] said, 'I'm going to kidnap your baby, I'm in your baby's room,'" Ellen said.

Read more: Parents reveal the 14 weirdest things they've seen on their baby monitor

Nathan sprinted upstairs and found their son safe, with no one else in the room, according to KPRC. Ellen says she then remembered reading a story about WiFi camera hacking, and figured that's how the man was able to speak through the monitor.

In a statement to INSIDER, a Nest spokesman said the company could not comment on specific cases, but that they were encouraging users to set up two-factor authentication as an extra layer of security:

"We have seen instances where a small number of Nest customers have reused passwords that were previously exposed through breaches on other websites, and made public. None of these breaches involved Nest. This exposes these customers to other people using the credentials to log into their Nest account. We are proactively alerting affected customers to reset their passwords and set up two-factor authentication, which adds another layer of account security. Customers can reach out to Nest customer support with questions or report anything suspicious to security@nest.com."

Ellen Rigney says her "immediate reaction was that there's somebody in here, somebody's in my son's room!" KPRC

The Rigneys said they immediately removed the WiFi baby monitor and now use one that doesn't connect to the internet. Ellen also said she reached out to Nest to complain about the issue, but says they "were no help at all" and "did not apologize."

"It's unnerving and unsettling," Ellen said. "Something that is supposed to make you feel better and instead it makes you feel the opposite, it makes you feel invaded and uncomfortable."