As others have said, there is a claim of breach of contract. But I will elaborate, should you decide to argue your position in administrative proceedings/remedies or in court. Equally important is that your situation will meet the prima facie elements of a claim of fraud if you as plaintiff are able to prove that the defendant employer "made a false representation intending thereby to induce [the] plaintiff to rely thereon and that the plaintiff justifiably relied thereon to his or her damage",
McNulty v. Chip, 116 A.3d 173, 182-83 (R.I. 2015).
But first I should clarify that the employer's deceitful or fraudulent practices strictly speaking are not a crime. Even if these practices were categorized as such in your jurisdiction's penal code, only the prosecutor would have "standing" to proceed in criminal court against the employer. At most, you and any co-plaintiffs have "standing" to sue the employer in civil court for the employer's unlawful or inequitable acts.
Here, the employer committed to a weekly bonus. Absent a mutually agreed clause (whether it was timely agreed upon, or agreed to be retroactive) permitting a longer delay, the parties ought to follow common, industry-wide practices. It is unreasonable for the employer not to pay a bonus of that magnitude within the next period (that is, a week, or a biweekly period) upon which it accrued. This is in contrast to an hourly wage, where it would be impractical to pay each work hour within the next hour.
Taxes aside, the employer is not allowed to reduce or eliminate the bonus for labor that was hired and performed under the bonus incentive. Doing so would squarely fit the elements of fraud as explained in the McNulty opinion. However, unless the contract forces the employer to maintain its bonus policy for a minimum duration, the employer can modify or terminate it only going forward (and hence each employer may decide whether to stay or quit).
The employer also committed to October 1 being the effective date of the incentive program. If the employer belatedly pays the bonus, his delay would be actionable only if you are able to prove that the employer's delay caused you losses which are reasonable, cognizable, and verifiable.
For instance, an allegation of the type "I got my bonus too late, so I was unable to buy my girlfriend a gift, and therefore she broke up with me" is neither reasonable nor legally cognizable as a loss. By contrast, if the bonus delay causes you penalties for making late payments or defaulting elsewhere, then the employer might be held liable for his delay (at least where the delay is unjustifiable).
If you decide to proceed against the employer, it is important that you as well as any prospective co-plaintiffs "exhaust administrative remedies" prior to filing suit in court. This is because, in one or more jurisdictions, bonuses are explicitly defined as fringe benefits and thus are unequivocally within the scope of statutes such as the Michigan Payment of Wages and Fringe Benefits Act. See MCL 408.471(e). Although this has not always been the case, nowadays Michigan judges are adamant that the verb "may" in MCL 408.481(1) means "shall" and that therefore it has a connotation of being "mandatory".
Thus, not exhausting (prior to suing in court) your administrative remedies pursuant to MCL 408.481 would cause your one or more of your claims to be dismissed in Michigan courts. That will continue to hold till Michigan judges bother to undust their dictionary and restore the prior case law on this issue.