The 2002 conviction of All Star linebacker Brian Banks on false charges of rape and kidnapping was dismissed in 2012, directly due to the efforts of the California Innocence Project.

Following his initial arrest for the alleged crimes, Banks, despite his protestations of innocence, faced a possible conviction, if the case had gone to trial, of 41-years-to-life, and reluctantly agreed to a plea bargain.

[6][20] After his release on probation, he arranged for a meeting with his accuser, Wanetta Gibson (who had contacted him through Facebook), at which she admitted on video that there had been no rape or kidnapping in 2002, and that their encounter had been completely consensual.

However, Semanchik was instrumental in putting together additional evidence supporting Banks' story, which led the district attorney to dismiss all charges against him and release him from sex-offender status, allowing him to resume his aborted sports career.

Part of the reason he was convicted of the murder was because an expert testified that an apparent bite mark on the victim's body was made by Richards.

However, despite the fact that medical records were produced that proved Cole had actually received his leg wound six years prior, he was convicted.

[30] CIP eventually discovered that a since-deceased attorney named Bruce Robertson had attempted to implicate Hanline in order to direct suspicion away from his own clients, and had intimidated potential witnesses.

[28] In addition, DNA testing pointed to Hanline's innocence, and it was established that the woman who testified against him had been on drugs, both on the night of the murder and at the time of her testimony.

[30] On November 24, 2014, Hanline was released from Ventura County Court a free man, and in April of the following year, a judge dismissed all charges against him, as the district attorney had decided not to retry the case.

[30] Having served 36 years behind bars, Hanline was the longest-incarcerated person whose conviction was reversed in the history of the State of California until Craig Coley was exonerated in 2017.

A medical examination of Vermeulen showed no sign of rape, and McMahon could prove that he was on vacation hundreds of miles away with his family at the time of the alleged assault.

The California Innocence Project partnered with the David House Agency to represent McMahon,[34] who was held in prison without bail in conditions described as "filthy and overcrowded with an overpowering stench.

"[34] Semanchik, who attended some of McMahon's bail hearings, commented, "If the authorities in the Philippines would have done even a shred of an investigation, they would've quickly realized that Scott couldn't have done this.

[38] The victim herself had been married to Googie Harris, Sr., who knew about the affair, had filed a restraining order against Cheek and had demanded custody of their daughters.

[41] "In this case," said Semanchik, "what stood out was it didn't make sense why somebody that would have committed the crime would have then just left their perfectly operable truck at the scene.

[40][43] Meanwhile, the CIP lobbied the legislature, in line with other states, to reduce the legal evidentiary standard, which would make the original 2014 DNA evidence to the judge sufficient to exonerate Roberts.

"[42] Under the law, wrongfully convicted inmates such as Roberts are entitled to receive $140 for each day incarcerated,[38] which would add up to over $1 million for his nearly 20 years in prison.

Determined to gain clemency from Governor Jerry Brown for twelve convicted prisoners whom they deemed to be "100 percent innocent" (including Guy Miles, Kim Long, William Richards and Michael Hanline, who were, at the time, still incarcerated), as well as to gain public awareness of the plight of wrongfully convicted prisoners, they walked a 700-mile route from the CIP's offices in San Diego to the Capitol at Sacramento to formally present their petition on behalf of the twelve to the governor.

[46] Adam Riojas, a CIP client freed after 14 years in prison, accompanied the marchers from San Diego to Oceanside, where he is now the pastor of a local chapel.

[5][11] In December of the same year, the California Innocence Project recreated the final (Sacramento) leg of the original march, from Raley Field to the governor's office at the Capitol.

"[47] Five of the twelve prisoners named in the petition (including Miles, Long, Richards and Hanline) have subsequently been freed through CIP's efforts.

For example, in a television interview, he criticized an existing law which states that a person accused of a crime must assert his or her innocence immediately, and cannot be exonerated if he or she does so only later on.

While conceding that the outcome of the particular case described was a positive one (that is, the predator was apprehended), Semanchik said, "We have to do a balancing act, where we have to say, 'keep law enforcement in check, do not allow them to get further down the road and expand upon their use of this.'

[50] In 2012, California referendum Proposition (Prop) 36 – which modified the law so that minor felony crimes (such as drug possession) wouldn't count as the third "strike" if a two-time felon gets convicted for the third time – passed by an overwhelming majority of voters.

[51] Semanchik supported the 2015 decision of the Los Angeles District Attorney's office to set up a team of veteran prosecutors to review the cases of incarcerated persons who present new evidence that they were wrongfully convicted.

[19] He has made public presentations about the wrongfully convicted and the Innocence March at, among many other venues, the USC School of Social Work, the SDSU School of Public Affairs, the UCSD Community Law Project, Point Loma Nazarene University, the Greater Inland Empire Municipal Law Association and the Defense Investigators Association Conference.

In an opinion piece published on the California Innocence Project website (representing his own views, rather than those of the organization), Semanchik argued strongly for prison reform, beginning with correcting America's "insane sentencing laws," and establishing "adequate (and relevant) job training, actual jobs upon release, and reentry programs to help inmates stay out.

In the article, he mentioned 16 CIP clients whom he believes are factually innocent, including some who remained incarcerated despite having their convictions overturned by a judge.

[17] In a 2015 article in Riverside Lawyer magazine, Semanchik maintained that the legal evidentiary standard in California to reverse convictions was too high.

He argued that that standard should be brought into line with those in other states, which have ruled that it is only necessary to prove that new evidence would probably have resulted in a different verdict if introduced at time of trial.