I am researching this as a part of a story plot involving hundreds to thousands of people who are members of a religious organization and who have agreed to buy and sell a particular company's shares in an attempt to create upward / downward momentum and to profit from the changes.
In the USA, are there laws that would make this illegal? If so, what laws are they?
Yes, this is prohibited by the Securities Exchange Act of 1934, Section 9(a)(2).
SEC. 9. (a) It shall be unlawful for any person, directly or indirectly, by the use of the mails or any means or instrumentality of interstate commerce, or of any facility of any national securities exchange, or for any member of a national securities exchange—
(2) To effect, alone or with 1 or more other persons, a series of transactions in any security other than a government security, any security not so registered, or in connection with any security-based swap or security-based swap agreement with respect to such security creating actual or apparent active trading in such security, or raising or depressing the price of such security, for the purpose of inducing the purchase or sale of such security by others.
