(ABC 6 News) – Barely a year after a devastating crash involving an SUV and an Amish buggy in which two children were killed, the court case continues with omnibus hearings for the twin sisters charged in the subsequent investigation.

At the time of the crash, the Fillmore County Sheriff’s Office reported that the driver was Sarah Beth Petersen.

However, the investigation that followed revealed details the made the case even more shocking.

Warrants from the sheriff’s office suggested it was Sarah’s twin sister, Samantha Jo Petersen, who had actually been behind the wheel when it collided with the buggy.

The case had become more complicated as law enforcement had to deal with keeping track of which sister had been where.

“In any case, depending on how complex it is, we just need to sort through the facts, make sure that law enforcement goes out and gathers all the evidence for us and then once we get all that evidence together, then that’s when we make that determination on charges,” said Fillmore County Attorney Brett Corson.

When those charges came down, it was alleged that Samantha had caused the crash while driving home form work, high on meth, and after the crash happened she switched places with Sarah to throw police off.

Samantha received 21 charges, many of them felonies, for the deaths and alleged driving under the influence.

Sarah received charges of her own – 16 felonies for taking responsibility and aiding an offender who committed criminal vehicular homicide.

Both sisters made their first court appearances back in March, neither making a plea.

Now, the next phase of the case will see the Petersens take part in omnibus hearings which will review evidence and determine if there was enough probable cause for the attorney’s charges to stick.

“Some of the challenges in this case are probable cause for certain charges,” said Corson. “If those charges are dismissed for lack of probable cause, then that could affect how the case proceeds.”

The same goes for evidence.

The Petersens’ defenses are arguing strongly against a recording of the sisters talking the day of the crash, while Sarah was in the back of a police car, which neither say they were aware of.

They are also considering a defense that dismisses Samantha’s “driving under the influence” charges, as she was not tested for drugs until a day after the crash.

Samantha Jo Petersen’s next court appearance will be an omnibus hearing on September 30.

Sarah Beth Petersen will appear for a settlement conference on October 21.