Two of her children were allegedly slaughtered by their nanny, and now Manhattan mom Marina Krim must face another devastating trauma — seeing the suspect’s lookalike sister every day.

The sibling of accused killer nanny Yoselyn Ortega is also a caregiver who, in a cruel twist of fate, baby-sits a girl who attends the same public school as the Krims’ only surviving daughter, Nessie.

Marina Krim found out the week before school started that the family that employs Celia Ortega lived near them once again.

“Can you imagine my anxiety as I am walking out of school with Nessie and on a daily basis wondering if I am going to run into this woman?’’ a distraught Marina wrote in an email to friends.

“She introduced us to the defendant who murdered our kids and Nessie’s sister and brother,’’ wrote Marina — who is still unable to utter or even type Yoselyn Ortega’s name — in the email, a copy of which was seen by The Post.

“Making it all worse, we now find out she lied about the defendant’s background to improve the chances of us hiring the defendant,” Marina alleges in the email, noting Celia Ortega is the one who recommended Yoselyn to her.

“Now, Marina is reliving her nightmare every day,’’ a close friend said about school pickup time.

On Oct. 25, 2012, Lucia Krim, 6, and Leo Krim, 2, were butchered in their Upper West Side home by a crazed, knife-wielding Yoselyn Ortega, authorities have said. Nessie was out of the apartment with her mom at the time.

Krim and her husband, Kevin, took Nessie and left the city for a couple of months to try to start over, relocating to Tribeca when they returned in early 2013.

But, unknown to them, the parents who employ Ortega’s sister, Henley and Xabi Vazquez, had moved from the Upper West Side themselves — to the same new neighborhood downtown.

Both families’ little girls now attend the highly rated PS 234.

“The most upsetting part is [the Krims] really moved as far away as possible from the scene and tried to rebuild their lives,” the friend said. “They’ve been doing great. And now it comes back to haunt them.”

Henley Vazquez declined to comment and Celia Ortega could not be reached.

The school principal, alerted to the heartbreaking scenario, tried to defuse the situation by asking the Vazquezes not to send the nanny to school pickups. But the family balked at the idea, Marina wrote in an email to pals. A deal was finally brokered by the school for Ortega to pick up 15 minutes after everyone else. Then, “the other day, I saw Celia three feet from me at 2:56 pm,” Marina said in the Friday email.

“My heart was racing, I was disturbed and angry . . . Celia was practically wearing a disguise, wearing big sunglasses and an olive-green quilted coat, she basically grabbed the daughter and rushed away, looking to me like she knew she was breaking the bargain. I just cannot deal with this anymore, enough is enough.”

The timing was awful: Leo would have turned 4 on Tuesday.

The Krims have since had another little boy and set up the Lulu & Leo Fund to support enrichment programs for kids.

Marina’s pal griped that a better school solution could be found.

“Babysitters are replaceable,’’ she said. “Marina’s babies will never come back.’’

Yoselyn Ortega is awaiting trial. She has pleaded not guilty.

Additional reporting by Elizabeth Hagen