Suspected Fraud on Buyer: Cambel B for Accountant/Book Keeper wanted job

Hi People Per Hour team,

I was wondering how do I report a suspected fraud case on a buyer as a freelancer? Below is the screenshot of the job that I have posted the offer on. After speaking with the hiring manager, I suspect that this maybe a fraudulent buyer.

I would really appreciate it if you let me know how to report suspected fraud. Thank you.

The reason for the suspicion is due to the following:

1. The buyer asked me to deposit a check from the company to purchase equipment so they were going to send me a check so I can deposit it and purchase the item. They stated the check should be the exact amount I needed after I ask about it. When I asked, how should the equipment be returned, the manager said no need to return it. According to the hiring manager, they are planning to open 15 locations and hire some online help at the moment. - This is suspicious because a company should not be sending funds to another person unless it's their paycheck. Also since these are company assets, even if the equipment needed $300, if they plan to hire 10 people, they are losing $3000. I don't think that is right.
2. Equipment fund raising - The buyer also asked if I can raise $500 out of my personal account to purchase the equipment. Again, I don't believe that is the correct process to request the freelancer to raise funds for equipment. Since this is suppose to be an online remote only job, why does the freelancer need equipment?
3. Offer Letter: Letterhead letter signature - I have received an offer letter from the company, however, the letterhead looks like it was cut from a screen shot and pasted onto the letter. The letter signature is someone else who is not the hiring manager with the title of just: supervisor; the signature also does not look like it's signed by the same person listed as the supervisor. Both look very unprofessional.
4. Offer Letter: Content - While interviewing with the hiring manager, there were mentioning of benefits and 401k after 90 days working with the company and also the equipment purchases. Although, the offer letter explain there will be benefits and stock options, it was not mentioned anywhere that the employee will receive it after 90 days of working. The equipment purchase arrangement is not even mentioned in the letter. The letter also had 1 extra blank page. As far as I understand, offer letters are reviewed, I think the blank page and leaving out certain contents is unprofessional as well. 
5. W2 or 1099 - Since the hiring manager stated that he is looking for someone to help online and the offer letter only mention the treatment for Full Time/Part Time positions, during my interview with the hiring manager, I asked if I will receive a W2 or 1099 at the end of the year. The hiring manager stated that the supervisor who will be training me will let me know. As the hiring manager who posted the job, I would imagine it's a very simple question, however, this person just avoid answering this question altogether.
6. Company website - I requested the company website from the hiring manager, would should be simple enough since most companies have websites for visibility purposes. The hiring manager tried to avoid answering the question by giving me the company mission. So I had to request the company website the 2nd time and the hiring manager finally provided it. After looking into the website and the company, it's a real company not located in the US, and I also didn't see anything about expanding into US on the website.