'Law & Order: SVU': Benson Interviews Mother Whose Family Was Murdered in New Episode Preview

Rizzoli & Isles star Sasha Alexander stops by Law & Order: Special Victims Unit this week to play a grieving mother dealing with the unthinkable.

In a preview for the episode, "Caretaker," Olivia Benson (Mariska Hargitay) and Amanda Rollins (Kelli Giddish) interview the mother, named Anna, after her husband Julian and their children are murdered in their sleep. At first, it did not look like Anna could give them much helpful information between her tears. Her husband was a writer who worked mostly at home, so he had no co-workers with a grudge.

However, Anna told Benson and Rollins that there is one other person with a key to their apartment, their nanny, Dolores Alvarez, who has worked for them for almost 10 years. Dolores was supposed to work the day after the murder, but never contacted the family.

"She's like family. She wouldn't hurt anyone," Alexander's character said.

In another preview scene, Dominick Carisi (Peter Scanavino) and Fin Tutuola (Ice-T) interview a possible suspect, Tom (Michael Laurence). Tom insisted he could not have done it, since they have been close friends with Julien for 20 years. Tom revealed that they were supposed to go to France to write together, until the trip was cancelled. Anna pulled the plug on the trip because she did not want to pay for it.

"Yes, I was angry, but not enough to kill," Tom said.

Tom believes that Julian knew Anna was not happy after her family's ski lodge fell into foreclosure.

"Somebody killed them over money?" Tom asked.

"One of the top two reasons people get dead," Fin reminded Tom.

"Caretaker" also guest stars Sandrine Holt, Soleidy Mendez, Gary Basaraba, Johanna Tolentino and Scott Bryce.

Alexander is best known for her role as Maura Isles in TNT's Rizzoli & Isles (which coincidentally co-starred Law & Order's Angie Harmon), Helene Runyon on Shameless, Caitlin Todd on NCIS and Gretchen Witter on Dawson's Creek. She recently starred in the indie movies, Ride and Amanda McKay.

SVU is now in its record-tying 20th season. It is now one of only three primetime drama series to reach 20 seasons, alongside Gunsmoke and the original Law & Order, and break that record next year.

There was a tabloid rumor that Hargitay was looking to leave the show, but she has made it clear herself she has no intention to leave.

"The joke with [then-showrunner] Warren Leight and I was season 16 was good, and we said season 17, we're going to phone it in," Hargitay said in June. "That was our schtick on set, because we were so exhausted. And then season 17, we killed it. And then season 18 ... we had a wobbly year. But season 19, I was like, 'I'm sorry, did anyone see the show?' [New showrunner Michael] Chernuchin, every single episode, he outdoes himself."

New episodes of Law & Order: SVU air at 10 p.m. ET on NBC.

Photo credit: Scott Gries/NBC