80 Main Street #580, West Orange N.J. 07052  |   973-761-2210
Close this search box.


Facing Criminal Prosecution is Frightening. Finding a strong advocate is critical to a successful outcome. John J. McMahon has been fighting for his clients since 1990. Experience has demonstrated that an aggressive challenge to the prosecution’s case must be mounted immediately. The Law Office of John J. McMahon will bring all necessary resources to bear to immediately investigate the charges.

Failure to act quickly can jeopardize an otherwise valid defense. Favorable video surveillance must be located and preserved before it is discarded or destroyed. Witnesses must be interviewed while their memories are still fresh. Scene photos/videos must be taken while the area in question remains unchanged. A vigorous investigation must be followed up with an aggressive motion practice. Failure to challenge the admissibility of the prosecution’s evidence will not only be detrimental to a favorable result at trial but will also risk any chance at relief on appeal.

John McMahon has experience in litigating all forms of pretrial motions.  When appropriate he has sought and obtained interlocutory relief from both the New Jersey Appellate Division and The New Jersey Supreme Court.  Criminal trials in today’s courtrooms frequently depend on expert testimony.  The Law Office of John J. McMahon is ready to engage the experts needed in mounting a strong defense. Whether pathologists, accountants, scientists, engineers or other forensic specialists, whoever is required will be engaged. In challenging the prosecution’s experts, John McMahon brings almost three decades worth of experience to bear in cross-examination skills.  Finally, if trial is required, few lawyers have successfully tried as many complex cases as John McMahon.

Practice Areas

Facing Criminal Prosecution is Frightening. Finding a strong advocate is critical to a successful outcome. John J. McMahon has been fighting for the accused since 1990. The Law Office of John J. McMahon will bring all necessary resources to bear to immediately investigate the charges.

In New Jersey Federal District Court and in New Jersey Superior Court: including RICO Prosecutions, Embezzlement, Money Laundering, Fraud etc.
Challenging all types of Forensic Evidence: including DNA; Blood-Splatter; Fingerprint Analysis; Ballistic Testing etc. As well as Challenging All Forms of Electronic Surveillance including Frye/Daubert motions to Preclude Unreliable Cell Tower Mapping and Warrentless Cell Phone Monitoring.
Mounting an Aggressive Trial Strategy involving Accident Reconstruction Engineering as well as Attacking Alleged BAC Levels
All Forms of Homicide (Murder, Aggravated Manslaughter, Reckless Manslaughter and Heat of Passion Manslaughter) as well as Attempted Murder, Assault, Sexual Assault, Kidnapping, Carjacking, Robbery and Carjacking.
In New Jersey Federal District Court, New Jersey Superior Court and Municipal Court (Economic Crimes, Drug Offenses, DUI’s, Endangering and Domestic Violence)
Representing juvenile defendants in delinquency actions in the New Jersey Superior Court-Family Division. Contesting applications for detention in order that the child may remain home during the pendency of the matter. Fighting attempts to waive the juvenile case to adult criminal court. Seeking treatment or diversion where appropriate. Litigating the matter by challenging the prosecution’s proofs at trial. At all times reminding the court and the prosecution that the primary purpose of the juvenile process is rehabilitation rather than punishment.
Appealing final judgments rendered in New Jersey Municipal Courts, New Jersey Superior Court or in the Federal District Court for the District of New Jersey. Filing and litigating motions for new trial and motions for reduction or change of sentence. Pursuing claims for Post-Conviction Relief(PCR) in New Jersey Superior Court and Writs of Habeas Corpus in Federal District Court.

Contact Us

Phone: 973-761-2210
80 Main Street Suite #580 West Orange NJ, 07052