Jennifer Dulos’ longtime nanny feared the worst when she went missing — and immediately suspected that estranged husband Fotis Dulos was “most likely involved,” court records show.

Lauren Almeida told detectives she sent Jennifer three text messages that weren’t returned on the afternoon of May 24, according to the warrant on which Fotis was arrested Tuesday on murder and kidnapping charges.

At 4 p.m., after taking the couple’s five kids to their maternal grandmother’s Fifth Avenue apartment, Almeida called her employer’s cellphone and was sent straight to voicemail.

“Immediately my stomach sank, and I had a feeling that something was wrong,” she told detectives.

“In the almost seven years that I have worked for Jennifer I NEVER EVER had a hard time reaching her and NEVER had an issue with her phone being off.”

Jennifer, who had an early morning doctor’s appointment in the city, was also was supposed to show up for her children’s orthodontist appointment at 4:40 p.m., but didn’t appear, the warrant says.

When Almeida learned that, she told detectives, “my first thought was that Fotis did something.”

“After pondering other possible scenarios, Ms. Almeida arrived back at the feeling that ‘something happened and that Fotis was most likely involved,'” the warrant says.

Almeida also told detectives about previously finding Jennifer’s handbag on the floor between the mudroom and kitchen in her New Canaan, Connecticut, house when she arrived there at 11:30 a.m., and about finding Jennifer’s “unopened granola bar and mug of tea on the kitchen counter,” the warrant says.

After Almeida and Jennifer’s close friend, Laurel Watts, reported Jennifer as missing to the New Canaan cops, Almeida called Fotis at 8:41 p.m., the warrant says.

“Fotis never asked me how Jennifer was doing the day previously, or when I had last heard from her or showed any concern about the fact that Jennifer was missing,” she told detectives.

Fotis, who was engaged in a bitter divorce battle with Jennifer at the time, has denied any involvement in her disappearance.

Defense lawyer Norman Pattis has also said he anticipates “beating these allegations at trial” and on Wednesday downplayed the evidence against his client following a court hearing in Stamford.

“What we have is a suspicious disappearance and an entirely circumstantial case,” Pattis told reporters.

“After this great length of time, I expected to see a forensic display that was breathtaking. I saw nothing.”