Rent is due 1st of month. Lessee is out of town. Someone wants to pay rent for lessee. Lessor put lock on property so lessee cant get in building about 10 days after rent was due. Lease states " if the lessee should fail to pay any of the monthly installments for rent for a period of more than 5 days after the same shall become due and payable, a five percent late charge will at lessor's option be assessed,. In addition, Lessor shall have the right to terminate this lease as provided below if, after 15 days the rent payment has not been made, which said termination shall be at the option of the lessor" My question is can the lessor put locks on the premises before the 12 day of the month and not let lessee get possession off property until rent is paid. Lessor has denied payment on the 12 from someone that is not on lease to keep lessee from losing personal property. Lessee is in jail.

Commercial leases are different from residential ones. In a commercial lease, what is written in the lease governs. If the lease doesn't not provide for the lessor to lock up the property, then the lessee can sue for loss of business (assuming the business would have remained open and operating while the lessee was absent.

Lessee needs to consult an attorney about suing the lessor. This is a situation about remedies after the fact. The law isn't going to prevent the lessor from locking up the property unless a court order is obtained to restrain the lessor.

... Lessor has denied payment on the 12 from someone that is not on lease to keep lessee from losing personal property. ...

Lessee's benefactor (the someone not on the lease) might want to consult an attorney. It isn't necessarily a "given" that personal property located within leased commercial premises may be kept by a landlord upon eviction of the tenant.