According to the ACAMS CAMS Study Guide, one of the methods that attorneys may use to facilitate money laundering is to make payments to third parties on behalf of their clients, using funds from their client accounts. This may obscure the source and destination of the funds, and create a false appearance of legitimate transactions. Therefore, making payment to various people is a red flag for potential money laundering in this situation.
References:
ACAMS CAMS Study Guide, 6th Edition, page 117
FATF Report on Money Laundering and Terrorist Financing Vulnerabilities of Legal Professionals, June 2013, page 341 AML/CFT Red Flags for Lawyers, AML-CFT.net, October 20202

Undermining the Legitimate Private Sector: One of the most serious microeconomic effects of money laundering is felt in the private sector. Money launderers are known to use front companies: businesses that appear legitimate and engage in legitimate business but are in fact controlled by criminals who commingle the proceeds of illicit activity with legitimate funds to hide the ill-gotten gains. These front companies have a competitive advantage over legitimate firms as they have access to substantial illicit funds, allowing them to subsidize products and services sold at below market rates. This makes it difficult for legitimate businesses to compete against front companies. Clearly, the management principles of these criminal enterprises are not consistent with traditional free market principles, which results in further negative macroeconomic effects Reference: http://people.exeter.ac.uk/watupman/undergrad/rtb/effects2.htm

Antiques are a potential tool for money laundering because they can be used to conceal, move, and convert illicit funds. Antiques can be of high value and often easily transported across borders, making them attractive for criminals who want to evade detection and reporting. Antiques can also be difficult to value and authenticate, creating a lack of transparency and accountability in the market. Criminals can exploit this to inflate or deflate the prices of antiques, or to use them as collateral for loans or other transactions. Antiques can also be used to layer or integrate illicit funds into the legitimate economy, by selling them through auction houses, dealers, or online platforms.
References:
CAMS Certification Package - 6th Edition, Chapter 4: Conducting and Supporting the Investigation Process, pp. 97-98.
Anti-money laundering and the art and antiquities market - a US and UK perspective, Mishcon de Reya LLP, 2022.
Antiques: an unconventional money laundering tool, The Express Tribune, 2023.
Art and Antiquities an Attractive Market for Money Laundering, FATF Argues, OCCRP, 2021.

Explanation
a financial institution must perform a continuing review of the account for a period of 90 days. The continuing review must include an analysis of any transactions that occur in the account, as well as any changes in the customer's risk profile. The review should be updated as needed to ensure that the customer is not engaging in any suspicious activities.