Under CCP 484.090, to secure an attachment, the plaintiff must, among other things, prove the probable validity of its claim and that the amount secured by the attachment is greater than zero. Under CCP 484.015(b)(4), the amount that the plaintiff seeks to secure by attachment is reduced by “the value of any security in the property of the defendant held by the plaintiff.” Here, plaintiff held an $8 million letter of credit from defendant’s bank, securing its obligations under the lease with plaintiff. This decision holds that the letter of credit is not a security interest in the defendant’s property, but instead an obligation of the issuing bank. So it cannot be subtracted from the $1 million in unpaid rent. However, the trial court erred in not weighing the evidence on defendant’s retaliatory eviction defense and its claim that plaintiff sought the attachment for an improper purpose. Under CCP 484.090(a), the plaintiff must show that ” the attachment is not sought for a purpose other than the recovery upon which the request for attachment is based” in order to secure an attachment. The retaliatory eviction defense and claim raised an issue regarding that element of an attachment which the trial court had to resolve before issuing a writ of attachment.